Apparatus and method for recovering fluids from a well and/or injecting fluids into a well

ABSTRACT

Methods and apparatus for diverting fluids either into or from a well are described. Some embodiments include a diverter conduit that is located in a bore of a tree. The invention relates especially but not exclusively to a diverter assembly connected to a wing branch of a tree. Some embodiments allow diversion of fluids out of a tree to a subsea processing apparatus followed by the return of at least some of these fluids to the tree for recovery. Alternative embodiments provide only one flowpath and do not include the return of any fluids to the tree. Some embodiments can be retro-fitted to existing trees, which can allow the performance of a new function without having to replace the tree. Multiple diverter assembly embodiments are also described.

RELATED APPLICATION

This Application is the U.S. National Phase Application of InternationalApplication No. PCT/GB2004/002329 entitled “APPARATUS AND METHOD FORRECOVERING FLUIDS FROM A WELL AND/OR INJECTING FLUIDS INTO A WELL”,filed on Jun. 1, 2004, which is a CIP of U.S. application Ser. No.10/651,703, filed on Aug. 29, 2003, now U.S. Pat. No. 7,111,687, andclaims benefit of U.S. Provisional Application No. 60/548,727 filed onFeb. 26, 2004; United Kingdom Application No. 0312543.2 filed on May 31,2003; United Kingdom Application No. 0405471.4 filed on Mar. 11, 2004;and United Kingdom Application No. 0405454.0 filed on Mar. 11, 2004.

Other related applications include U.S. application Ser. No. 10/009,991filed on Jul. 16, 2002, now U.S. Pat. No. 6,637,514; U.S. applicationSer. No. 10/415,156 filed on Apr. 25, 2003, now U.S. Pat. No. 6,823,941;U.S. application Ser. No. 10/590,563 filed on Dec. 13, 2007; U.S.application Ser. No. 12/441,119 filed on Mar. 12, 2009; U.S. applicationSer. No. 12/515,534 filed on May 19, 2009; U.S. application Ser. No.12/515,729 filed on May 20, 2009; U.S. application Ser. No. 12/541,934filed on Aug. 15, 2009; U.S. application Ser. No. 12/541,936 filed Aug.15, 2009; U.S. application Ser. No. 12/541,937 filed on Aug. 15, 2009;U.S. application Ser. No. 12/541,938 filed on Aug. 15, 2009; U.S.application Ser. No. 12/768,324 filed on Apr. 27, 2010; U.S. applicationSer. No. 12/768,332 filed on Apr. 27, 2010; and U.S. application Ser.No. 12/768,337 filed on April 27, 2010.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for divertingfluids. Embodiments of the invention can be used for recovery andinjection. Some embodiments relate especially but not exclusively torecovery and injection, into either the same, or a different well.

DESCRIPTION OF THE RELATED ART

Christmas trees are well known in the art of oil and gas wells, andgenerally comprise an assembly of pipes, valves and fittings installedin a wellhead after completion of drilling and installation of theproduction tubing to control the flow of oil and gas from the well.Subsea christmas trees typically have at least two bores one of whichcommunicates with the production tubing (the production bore), and theother of which communicates with the annulus (the annulus bore).

Typical designs of christmas tree have a side outlet (a production wingbranch) to the production bore closed by a production wing valve forremoval of production fluids from the production bore. The annulus borealso typically has an annulus wing branch with a respective annulus wingvalve. The top of the production bore and the top of the annulus boreare usually capped by a christmas tree cap which typically seals off thevarious bores in the christmas tree, and provides hydraulic channels foroperation of the various valves in the christmas tree by means ofintervention equipment, or remotely from an offshore installation.

Wells and trees are often active for a long time, and wells from adecade ago may still be in use today. However, technology has progresseda great deal during this time, for example, subsea processing of fluidsis now desirable. Such processing can involve adding chemicals,separating water and sand from the hydrocarbons, etc. Furthermore, it issometimes desired to take fluids from one well and inject a component ofthese fluids into another well, or into the same well. To do any ofthese things involves breaking the pipework attached to the outlet ofthe wing branch, inserting new pipework leading to this processingequipment, alternative well, etc. This provides the problem and largeassociated risks of disconnecting pipe work which has been in place fora considerable time and which was never intended to be disconnected.Furthermore, due to environmental regulations, no produced fluids areallowed to leak out into the ocean, and any such unanticipated andunconventional disconnection provides the risk that this will occur.

Conventional methods of extracting fluid from wells involves recoveringall of the fluids along pipes to the surface (e.g. a rig or even toland) before the hydrocarbons are separated from the unwanted sand andwater. Conveying the sand and water such great distances is wasteful ofenergy. Furthermore, fluids to be injected into a well are oftenconveyed over significant distances, which is also a waste of energy.

In low pressure wells, it is generally desirable to boost the pressureof the production fluids flowing through the production bore, and thisis typically done by installing a pump or similar apparatus after theproduction wing valve in a pipeline or similar leading from the sideoutlet of the christmas tree. However, installing such a pump in anactive well is a difficult operation, for which production must ceasefor some time until the pipeline is cut, the pump installed, and thepipeline resealed and tested for integrity.

A further alternative is to pressure boost the production fluids byinstalling a pump from a rig, but this requires a well intervention fromthe rig, which can be even more expensive than breaking the subsea orseabed pipework.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided adiverter assembly for a manifold of an oil or gas well, comprising ahousing having an internal passage, wherein the diverter assembly isadapted to connect to a branch of the manifold.

According to a second aspect of the invention there is provided adiverter assembly adapted to be inserted within a manifold branch bore,wherein the diverter assembly includes a separator to divide the branchbore into two separate regions.

The oil or gas well is typically a subsea well but the invention isequally applicable to topside wells.

The manifold may be a gathering manifold at the junction of several flowlines carrying production fluids from, or conveying injection fluids to,a number of different wells. Alternatively, the manifold may bededicated to a single well; for example, the manifold may comprise achristmas tree.

By “branch” we mean any branch of the manifold, other than a productionbore of a tree. The wing branch is typically a lateral branch of thetree, and can be a production or an annulus wing branch connected to aproduction bore or an annulus bore respectively.

Optionally, the housing is attached to a choke body. “Choke body” canmean the housing which remains after the manifold's standard choke hasbeen removed. The choke may be a choke of a tree, or a choke of anyother kind of manifold.

The diverter assembly could be located in a branch of the manifold (or abranch extension) in series with a choke. For example, in an embodimentwhere the manifold comprises a tree, the diverter assembly could belocated between the choke and the production wing valve or between thechoke and the branch outlet. Further alternative embodiments could havethe diverter assembly located in pipework coupled to the manifold,instead of within the manifold itself. Such embodiments allow thediverter assembly to be used in addition to a choke, instead ofreplacing the choke.

Embodiments where the diverter assembly is adapted to connect to abranch of a tree means that the tree cap does not have to be removed tofit the diverter assembly. Embodiments of the invention can be easilyretrofitted to existing trees.

Preferably, the diverter assembly is locatable within a bore in thebranch of the manifold.

Optionally, the internal passage of the diverter assembly is incommunication with the interior of the choke body, or other part of themanifold branch.

The invention provides the advantage that fluids can be diverted fromtheir usual path between the well bore and the outlet of the wingbranch. The fluids may be produced fluids being recovered and travellingfrom the well bore to the outlet of a tree. Alternatively, the fluidsmay be injection fluids travelling in the reverse direction into thewell bore. As the choke is standard equipment, there are well-known andsafe techniques of removing and replacing the choke as it wears out. Thesame tried and tested techniques can be used to remove the choke fromthe choke body and to clamp the diverter assembly onto the choke body,without the risk of leaking well fluids into the ocean. This enables newpipe work to be connected to the choke body and hence enables safere-routing of the produced fluids, without having to undertake theconsiderable risk of disconnecting and reconnecting any of the existingpipes (e.g. the outlet header).

Some embodiments allow fluid communication between the well bore and thediverter assembly. Other embodiments allow the well bore to be separatedfrom a region of the diverter assembly. The choke body may be aproduction choke body or an annulus choke body.

Preferably, a first end of the diverter assembly is provided with aclamp for attachment to a choke body or other part of the manifoldbranch.

Optionally, the housing is cylindrical and the internal passage extendsaxially through the housing between opposite ends of the housing.Alternatively, one end of the internal passage is in a side of thehousing.

Typically, the diverter assembly includes separation means to providetwo separate regions within the diverter assembly. Typically, each ofthese regions has a respective inlet and outlet so that fluid can flowthrough both of these regions independently.

Optionally, the housing includes an axial insert portion.

Typically, the axial insert portion is in the form of a conduit.Typically, the end of the conduit extends beyond the end of the housing.Preferably, the conduit divides the internal passage into a first regioncomprising the bore of the conduit and a second region comprising theannulus between the housing and the conduit.

Optionally, the conduit is adapted to seal within the inside of thebranch (e.g. inside the choke body) to prevent fluid communicationbetween the annulus and the bore of the conduit.

Alternatively, the axial insert portion is in the form of a stem.Optionally, the axial insert portion is provided with a plug adapted toblock an outlet of the christmas tree, or other kind of manifold.Preferably, the plug is adapted to fit within and seal inside a passageleading to an outlet of a branch of the manifold.

Optionally, the diverter assembly provides means for diverting fluidsfrom a first portion of a first flowpath to a second flowpath, and meansfor diverting the fluids from a second flowpath to a second portion of afirst flowpath.

Preferably, at least a part of the first flowpath comprises a branch ofthe manifold.

The first and second portions of the first flowpath could comprise thebore and the annulus of a conduit.

According to a third aspect of the present invention there is provided amanifold having a branch and a diverter assembly according to the firstor second aspects of the invention.

Optionally, the diverter assembly is attached to the branch so that theinternal passage of the diverter assembly is in communication with theinterior of the branch.

Optionally, the manifold has a wing branch outlet, and the internalpassage of the diverter assembly is in fluid communication with the wingbranch outlet.

Optionally, a region defined by the diverter assembly is separate fromthe production bore of the well. Optionally, the internal passage of thediverter assembly is separated from the well bore by a closed valve inthe manifold.

Alternatively, the diverter assembly is provided with an insert in theform of a conduit which defines a first region comprising the bore ofthe conduit, and a second separate region comprising the annulus betweenthe conduit and the housing. Optionally, one end of the conduit issealed inside the choke body or other part of the branch, to preventfluid communication between the first and second regions.

Optionally, the annulus between the conduit and the housing is closed sothat the annulus is in communication with the branch only.

Alternatively, the annulus has an outlet for connection to furtherpipes, so that the second region provides a flowpath which is separatefrom the first region formed by the bore of the conduit.

Optionally, the first and second regions are connected by pipework.Optionally, a processing apparatus is connected in the pipework so thatfluids are processed whilst passing through the connecting pipework.

Typically, the processing apparatus is chosen from at least one of: apump; a process fluid turbine; injection apparatus for injecting gas orsteam; chemical injection apparatus; a fluid riser; measurementapparatus; temperature measurement apparatus; flow rate measurementapparatus; constitution measurement apparatus; consistency measurementapparatus; gas separation apparatus; water separation apparatus; solidsseparation apparatus; and hydrocarbon separation apparatus.

Optionally, the diverter assembly provides a barrier to separate abranch outlet from a branch inlet. The barrier may separate a branchoutlet from a production bore of a tree. Optionally, the barriercomprises a plug, which is typically located inside the choke body (orother part of the manifold branch) to block the branch outlet.Optionally, the plug is attached to the housing by a stem which extendsaxially through the internal passage of the housing.

Alternatively, the barrier comprises a conduit of the diverter assemblywhich is engaged within the choke body or other part of the branch.

Optionally, the manifold is provided with a conduit connecting the firstand second regions.

Optionally, a first set of fluids are recovered from a first well via afirst diverter assembly and combined with other fluids in a communalconduit, and the combined fluids are then diverted into an export linevia a second diverter assembly connected to a second well.

According to a fourth aspect of the present invention, there is provideda method of diverting fluids, comprising: connecting a diverter assemblyto a branch of a manifold, wherein the diverter assembly comprises ahousing having an internal passage; and diverting the fluids through thehousing.

According to a fifth aspect of the present invention there is provided amethod of diverting well fluids, the method including the steps of:

-   -   diverting fluids from a first portion of a first flowpath to a        second flowpath and diverting the fluids from the second        flowpath back to a second portion of the first flowpath;    -   wherein the fluids are diverted by at least one diverter        assembly connected to a branch of a manifold.

The diverter assembly is optionally located within a choke body;alternatively, the diverter assembly may be coupled in series with achoke. The diverter assembly may be located in the manifold branchadjacent to the choke, or it may be included within a separate extensionportion of the manifold branch.

Typically, the method is for recovering fluids from a well, and includesthe final step of diverting fluids to an outlet of the first flowpathfor recovery therefrom. Alternatively or additionally, the method is forinjecting fluids into a well.

Optionally, the internal passage of the diverter assembly is incommunication with the interior of the branch.

The fluids may be passed in either direction through the diverterassembly.

Typically, the diverter assembly includes separation means to providetwo separate regions within the diverter assembly, and the method mayincludes the step of passing fluids through one or both of theseregions.

Optionally, fluids are passed through the first and the second regionsin the same direction. Alternatively, fluids are passed through thefirst and the second regions in opposite directions.

Optionally, the fluids are passed through one of the first and secondregions and subsequently at least a proportion of these fluids are thenpassed through the other of the first and the second regions.Optionally, the method includes the step of processing the fluids in aprocessing apparatus before passing the fluids back to the other of thefirst and second regions.

Alternatively, fluids may be passed through only one of the two separateregions. For example, the diverter assembly could be used to provide aconnection between two flow paths which are unconnected to the wellbore, e.g. between two external fluid lines. Optionally, fluids couldflow only through a region which is sealed from the branch. For exampleif the separate regions were provided with a conduit sealed within amanifold branch, fluids may flow through the bore of the conduit only. Aflowpath could connect the bore of the conduit to a well bore(production or annulus bore) or another main bore of the tree to bypassthe manifold branch. This flowpath could optionally link a regiondefined by the diverter assembly to a well bore via an aperture in thetree cap.

Optionally, the first and second regions are connected by pipework.Optionally, a processing apparatus is connected in the pipework so thatfluids are processed whilst passing through the connecting pipework.

The processing apparatus can be, but is not limited to, any of thosedescribed above.

Typically, the method includes the step of removing a choke from thechoke body before attaching the diverter assembly to the choke body.

Optionally, the method includes the step of diverting fluids from afirst portion of a first flowpath to a second flowpath and diverting thefluids from the second flowpath to a second portion of the firstflowpath.

For recovering production fluids, the first portion of the firstflowpath is typically in communication with the production bore, and thesecond portion of the first flowpath is typically connected to apipeline for carrying away the recovered fluids (e.g. to the surface).For injecting fluids into the well, the first portion of the firstflowpath is typically connected to an external fluid line, and thesecond portion of the first flowpath is in communication with theannulus bore. Optionally, the flow directions may be reversed.

The method provides the advantage that fluids can be diverted (e.g.recovered or injected into the well, or even diverted from anotherroute, bypassing the well completely) without having to remove andreplace any pipes already attached to the manifold branch outlet (e.g. aproduction wing branch outlet).

Optionally, the method includes the step of recovering fluids from awell and the step of injecting fluids into the well. Optionally, some ofthe recovered fluids are re-injected into the same well, or a differentwell.

For example, the production fluids could be separated into hydrocarbonsand water; the hydrocarbons being returned to the first flowpath forrecovery therefrom, and the water being returned and injected into thesame or a different well.

Optionally, both of the steps of recovering fluids and injecting fluidsinclude using respective flow diverter assemblies. Alternatively, onlyone of the steps of recovering and injecting fluids includes using adiverter assembly.

Optionally, the method includes the step of diverting the fluids througha processing apparatus.

According to a sixth aspect of the present invention there is provided amanifold having a first diverter assembly according to the first aspectof the invention connected to a first branch and a second diverterassembly according to the first aspect of the invention connected to asecond branch.

Typically, the manifold comprises a tree and the first branch comprisesa production wing branch and the second branch comprises an annulus wingbranch.

According to a seventh aspect of the present invention, there isprovided a manifold having a first bore having an outlet; a second borehaving an outlet; a first diverter assembly connected to the first bore;a second diverter assembly connected to the second bore; and a flowpathconnecting the first and second diverter assemblies.

Typically at least one of the first and second diverter assembliesblocks a passage in the manifold between a bore of the manifold and itsrespective outlet. Optionally, the manifold comprises a tree, and thefirst bore comprises a production bore and the second bore comprises anannulus bore.

Certain embodiments have the advantage that the first and seconddiverter assemblies can be connected together to allow the unwantedparts of the produced fluids (e.g. water and sand) to be directlyinjected back into the well, instead of being pumped away with thehydrocarbons. The unwanted materials can be extracted from thehydrocarbons substantially at the wellhead, which reduces the quantityof production fluids to be pumped away, thereby saving energy. The firstand second diverter assemblies can alternatively or additionally be usedto connect to other kinds of processing apparatus (e.g. the typesdescribed with reference to other aspects of the invention), such as abooster pump, filter apparatus, chemical injection apparatus, etc. toallow adding or taking away of substances and adjustment of pressure tobe carried out adjacent to the wellhead. The first and second diverterassemblies enable processing to be performed on both fluids beingrecovered and fluids being injected. Preferred embodiments of theinvention enable both recovery and injection to occur simultaneously inthe same well.

Typically, the first and second diverter assemblies are connected to aprocessing apparatus. The processing apparatus can be any of thosedescribed with reference to other aspects of the invention.

The diverter assembly may be a diverter assembly as described accordingto any aspect of the invention.

Typically, a tubing system adapted to both recover and inject fluids isalso provided. Preferably, the tubing system is adapted tosimultaneously recover and inject fluids.

According to a eighth aspect of the present invention there is provideda method of recovery of fluids from, and injection of fluids into, awell, wherein the well has a manifold that includes at least one boreand at least one branch having an outlet, the method including the stepsof:

-   -   blocking a passage in the manifold between a bore of the        manifold and its respective branch outlet;    -   diverting fluids recovered from the well out of the manifold;        and    -   injecting fluids into the well;    -   wherein neither the fluids being diverted out of the manifold        nor the fluids being injected travel through the branch outlet        of the blocked passage.

Preferably, the method is performed using a diverter assembly accordingto any aspect of the invention.

Preferably, a processing apparatus is coupled to the second flowpath.The processing apparatus can be any of the ones defined in any aspect ofthe invention.

Typically, the processing apparatus separates hydrocarbons from the restof the produced fluids. Typically, the non-hydrocarbon components of theproduced fluids are diverted to the second diverter assembly to provideat least one component of the injection fluids.

Optionally, at least one component of the injection fluids is providedby an external fluid line which is not connected to the production boreor to the first diverter assembly.

Optionally, the method includes the step of diverting at least some ofthe injection fluids from a first portion of a first flowpath to asecond flowpath and diverting the fluids from the second flowpath backto a second portion of the first flowpath for injection into the annulusbore of the well.

Typically, the steps of recovering fluids from the well and injectingfluids into the well are carried out simultaneously.

According to a ninth aspect of the present invention there is provided awell assembly comprising:

-   a first well having a first diverter assembly;-   a second well having a second diverter assembly; and-   a flowpath connecting the first and second diverter assemblies.

Typically, each of the first and second wells has a tree having arespective bore and a respective outlet, and at least one of thediverter assemblies blocks a passage in the tree between its respectivetree bore and its respective tree outlet.

Typically, an alternative outlet is provided, and the diverter assemblydiverts fluids into a path leading to the alternative outlet.

Optionally, at least one of the first and second diverter assemblies islocated within the production bore of its respective tree. Optionally,at least one of the first and second diverter assemblies is connected toa wing branch of its respective tree.

According to a tenth aspect of the present invention there is provided amethod of diverting fluids from a first well to a second well via atleast one manifold, the method including the steps of:

-   -   blocking a passage in the manifold between a bore of the        manifold and a branch outlet of the manifold; and    -   diverting at least some of the fluids from the first well to the        second well via a path not including the branch outlet of the        blocked passage.

Optionally the at least one manifold comprises a tree of the first welland the method includes the further step of returning a portion of therecovered fluids to the tree of the first well and thereafter recoveringthat portion of the recovered fluids from the outlet of the blockedpassage.

According to an eleventh aspect of the present invention there isprovided a method of recovery of fluids from, and injection of fluidsinto, a well having a manifold; wherein at least one of the steps ofrecovery and injection includes diverting fluids from a first portion ofa first flowpath to a second flowpath and diverting the fluids from thesecond flowpath to a second portion of the first flowpath

Optionally, recovery and injection is simultaneous. Optionally, some ofthe recovered fluids are re-injected into the well.

According to a twelfth aspect of the present invention there is provideda method of recovering fluids from a first well and re-injecting atleast some of these recovered fluids into a second well, wherein themethod includes the steps of diverting fluids from a first portion of afirst flowpath to a second flowpath, and diverting at least some ofthese fluids from the second flowpath to a second portion of the firstflowpath.

Typically, the fluids are recovered from the first well via a firstdiverter assembly, and wherein the fluids are re-injected into thesecond well via a second diverter assembly.

Typically, the method also includes the step of processing theproduction fluids in a processing apparatus connected between the firstand second wells.

Optionally, the method includes the further step of returning a portionof the recovered fluids to the first diverter assembly and thereafterrecovering that portion of the recovered fluids via the first diverterassembly.

According to a thirteenth aspect of the presentz invention there isprovided a method of recovering fluids from, or injecting fluids into, awell, including the step of diverting the fluids between a well bore anda branch outlet whilst bypassing at least a portion of the branch.

Such embodiments are useful to divert fluids to a processing apparatusand then to return them to the wing branch outlet for recovery via astandard export line attached to the outlet. The method is also usefulif a wing branch valve gets stuck shut.

Optionally, the fluids are diverted via the tree cap

According to a fourteenth aspect of the present invention there isprovided a method of injecting fluids into a well, the method comprisingdiverting fluids from a first portion of a first flowpath to a secondflowpath and diverting the fluids from the second flowpath into a secondportion of the first flowpath.

Optionally, the method is performed using a diverter assembly accordingto any aspect of the invention. The diverter assembly may be locatablein a wide range of places, including, but not limited to: the productionbore, the annulus bore, the production wing branch, the annulus wingbranch, a production choke body, an annulus choke body, a tree cap orexternal conduits connected to a tree. The diverter assembly is notnecessarily connected to a tree, but may instead be connected to anothertype of manifold. The first and second flowpaths could comprise some orall of any part of the manifold.

Typically the first flowpath is a production bore or production line,and the first portion of it is typically a lower part near to thewellhead. Alternatively, the first flowpath comprises an annulus bore.The second portion of the first flowpath is typically a downstreamportion of the bore or line adjacent a branch outlet, although the firstor second portions can be in the branch or outlet of the first flowpath.

The diversion of fluids from the first flowpath allows the treatment ofthe fluids (e.g. with chemicals) or pressure boosting for more efficientrecovery before re-entry into the first flowpath.

Optionally the second flowpath is an annulus bore, or a conduit insertedinto the first flowpath. Other types of bore may optionally be used forthe second flowpath instead of an annulus bore.

Typically the flow diversion from the first flowpath to the secondflowpath is achieved by a cap on the tree. Optionally, the cap containsa pump or treatment apparatus, but this can be provided separately, orin another part of the apparatus, and in most embodiments of this type,flow will be diverted via the cap to the pump etc and returned to thecap by way of tubing. A connection typically in the form of a conduit istypically provided to transfer fluids between the first and secondflowpaths.

Typically, the diverter assembly can be formed from high grade steels orother metals, using e.g. resilient or inflatable sealing means asrequired.

The assembly may include outlets for the first and second flowpaths, fordiversion of the fluids to a pump or treatment assembly, or otherprocessing apparatus as described in this application.

The assembly optionally comprises a conduit capable of insertion intothe first flowpath, the assembly having sealing means capable of sealingthe conduit against the wall of the production bore. The conduit mayprovide a flow diverter through its central bore which typically leadsto a christmas tree cap and the pump mentioned previously. The sealeffected between the conduit and the first flowpath prevents fluid fromthe first flowpath entering the annulus between the conduit and theproduction bore except as described hereinafter. After passing through atypical booster pump, squeeze or scale chemical treatment apparatus, thefluid is diverted into the second flowpath and from there to a crossoverback to the first flowpath and first flowpath outlet.

The assembly and method are typically suited for subsea production wellsin normal mode or during well testing, but can also be used in subseawater injection wells, land based oil production injection wells, andgeothermal wells.

The pump can be powered by high pressure water or by electricity whichcan be supplied direct from a fixed or floating offshore installation,or from a tethered buoy arrangement, or by high pressure gas from alocal source.

The cap preferably seals within christmas tree bores above the uppermaster valve. Seals between the cap and bores of the tree are optionallyO-ring, inflatable, or preferably metal-to-metal seals. The cap can beretrofitted very cost effectively with no disruption to existingpipework and minimal impact on control systems already in place.

The typical design of the flow diverters within the cap can vary withthe design of tree, the number, size, and configuration of the diverterchannels being matched with the production and annulus bores, and othersas the case may be. This provides a way to isolate the pump from theproduction bore if needed, and also provides a bypass loop.

The cap is typically capable of retrofitting to existing trees, and manyinclude equivalent hydraulic fluid conduits for control of tree valves,and which match and co-operate with the conduits or other controlelements of the tree to which the cap is being fitted.

In most preferred embodiments, the cap has outlets for production andannulus flow paths for diversion of fluids away from the cap.

In accordance with a fifteenth aspect of the invention there is alsoprovided a pump adapted to fit within a bore of a manifold. The manifoldoptionally comprises a tree, but can be any kind of manifold for an oilor gas well, such as a gathering manifold.

According to a sixteenth aspect of the present invention there isprovided a diverter assembly having a pump according to the fifteenthaspect of the present invention.

The diverter assembly can be a diverter assembly according to any aspectof the invention, but it is not limited to these.

The tree is typically a subsea tree, such as a christmas tree, typicallyon a subsea well, but a topside tree (or other topside manifold)connected to a topside well could also be appropriate. Horizontal orvertical trees are equally suitable for use of the invention.

The bore of the tree may be a production bore. However, the diverterassembly and pump could be located in any bore of the tree, for example,in a wing branch bore.

The flow diverter typically incorporates diverter means to divert fluidsflowing through the bore of the tree from a first portion of the bore,through the pump, and back to a second portion of the bore for recoverytherefrom via an outlet, which is typically the production wing valve.

The first portion from which the fluids are initially diverted istypically the production bore/other bore/line of the well, and flow fromthis portion is typically diverted into a diverter conduit sealed withinthe bore. Fluid is typically diverted through the bore of the diverterconduit, and after passing therethrough, and exiting the bore of thediverter conduit, typically passes through the annulus created betweenthe diverter conduit and the bore or line. At some point on the divertedfluid path, the fluid passes through the pump internally of the tree,thereby minimising the external profile of the tree, and reducing thechances of damage to the pump.

The pump is typically powered by a motor, and the type of motor can bechosen from several different forms. In some embodiments of theinvention, a hydraulic motor, a turbine motor or moineau motor can bedriven by any well-known method, for example an electro-hydraulic powerpack or similar power source, and can be connected, either directly orindirectly, to the pump. In certain other embodiments, the motor can bean electric motor, powered by a local power source or by a remote powersource.

Certain embodiments of the present invention allow the construction ofwellhead assemblies that can drive the fluid flow in differentdirections, simply by reversing the flow of the pump, although in someembodiments valves may need to be changed (e.g. reversed) depending onthe design of the embodiment.

The diverter assembly typically includes a tree cap that can beretrofitted to existing designs of tree, and can integrally contain thepump and/or the motor to drive it.

The flow diverter preferably also comprises a conduit capable ofinsertion into the bore, and may have sealing means capable of sealingthe conduit against the wall of the bore. The flow diverter typicallyseals within christmas tree production bores above an upper master valvein a conventional tree, or in the tubing hangar of a horizontal tree,and seals can be optionally O-ring, inflatable, elastomeric or metal tometal seals. The cap or other parts of the flow diverter can comprisehydraulic fluid conduits. The pump can optionally be sealed within theconduit.

According to a seventeenth aspect of the invention there is provided amethod of recovering production fluids from a well having a manifold,the manifold having an integral pump located in a bore of the manifold,and the method comprising diverting fluids from a first portion of abore of the manifold through the pump and into a second portion of thebore.

According to an eighteenth aspect of the present invention there isprovided a christmas tree having a diverter assembly sealed in a bore ofthe tree, wherein the diverter assembly comprises a separator whichdivides the bore of the tree into two separate regions, and whichextends through the tree bore and into the production zone of the well.

Optionally, the at least one diverter assembly comprises a conduit andat least one seal; the conduit optionally comprises a gas injectionline.

This invention may be used in conjunction with a further diverterassembly according to any other aspect of the invention, or with adiverter assembly in the form of a conduit which is sealed in theproduction bore. Both diverter assemblies may comprise conduits; oneconduit may be arranged concentrically within the other conduit toprovide concentric, separate regions within the production bore.

According to a nineteenth aspect of the present invention there isprovided a method of diverting fluids, including the steps of:

-   -   providing a fluid diverter assembly sealed in a bore of a tree        to form two separate regions in the bore and extending into the        production zone of the well;    -   injecting fluids into the well via one of the regions; and    -   recovering fluids via the other of the regions.

The injection fluids are typically gases; the method may include thesteps of blocking a flowpath between the bore of the tree and aproduction wing outlet and diverting the recovered fluids out of thetree along an alternative route. The recovered fluids may be divertingthe recovered fluids to a processing apparatus and returning at leastsome of these recovered fluids to the tree and recovering these fluidsfrom a wing branch outlet. The recovered fluids may undergo any of theprocesses described in this invention, and may be returned to the treefor recovery, or not, (e.g. they may be recovered from a fluid riser)according to any of the described methods and flowpaths.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Embodiments of the invention will now be described by way of exampleonly and with reference to the accompanying drawings in which:

FIG. 1 is a side sectional view of a typical production tree;

FIG. 2 is a side view of the FIG. 1 tree with a diverter cap in place;

FIG. 3 a is a view of the FIG. 1 tree with a second embodiment of a capin place;

FIG. 3 b is a view of the FIG. 1 tree with a third embodiment of a capin place;

FIG. 4 a is a view of the FIG. 1 tree with a fourth embodiment of a capin place; and

FIG. 4 b is a side view of the FIG. 1 tree with a fifth embodiment of acap in place.

FIG. 5 shows a side view of a first embodiment of a diverter assemblyhaving an internal pump;

FIG. 6 shows a similar view of a second embodiment with an internalpump;

FIG. 7 shows a similar view of a third embodiment with an internal pump;

FIG. 8 shows a similar view of a fourth embodiment with an internalpump;

FIG. 9 shows a similar view of a fifth embodiment with an internal pump;

FIGS. 10 and 11 show a sixth embodiment with an internal pump;

FIGS. 12 and 13 show a seventh embodiment with an internal pump;

FIGS. 14 and 15 show an eighth embodiment with an internal pump;

FIG. 16 shows a ninth embodiment with an internal pump;

FIG. 17 shows a schematic diagram of the FIG. 2 embodiment coupled toprocessing apparatus;

FIG. 18 shows a schematic diagram of two embodiments of the inventionengaged with a production well and an injection well respectively, thetwo wells being connected via a processing apparatus;

FIG. 19 shows a specific example of the FIG. 18 embodiment;

FIG. 20 shows a cross-section of an alternative embodiment, which has adiverter conduit located inside a choke body;

FIG. 21 shows a cross-section of the embodiment of FIG. 20 located in ahorizontal tree;

FIG. 22 shows a cross-section of a further embodiment, similar to theFIG. 20 embodiment, but also including a choke;

FIG. 23 shows a cross-sectional view of a tree having a first diverterassembly coupled to a first branch of the tree and a second diverterassembly coupled to a second branch of the tree;

FIG. 24 shows a schematic view of the FIG. 23 assembly used inconjunction with a first downhole tubing system;

FIG. 25 shows an alternative embodiment of a downhole tubing systemwhich could be used with the FIG. 23 assembly;

FIGS. 26 and 27 show alternative embodiments of the invention, eachhaving a diverter assembly coupled to a modified christmas tree branchbetween a choke and a production wing valve;

FIGS. 28 and 29 show further alternative embodiments, each having adiverter assembly coupled to a modified christmas tree branch below achoke;

FIG. 30 shows a first diverter assembly used to divert fluids from afirst well and connected to an inlet header; and a second diverterassembly used to divert fluids from a second well and connected to anoutput header;

FIG. 31 shows a cross-sectional view of an embodiment of a diverterassembly having a central stem;

FIG. 32 shows a cross-sectional view of an embodiment of a diverterassembly not having a central conduit;

FIG. 33 shows a cross-sectional view of a further embodiment of adiverter assembly; and

FIG. 34 shows a cross-sectional view of a possible method of use of theFIG. 33 embodiment to provide a flowpath bypassing a wing branch of thetree;

FIG. 35 shows a schematic diagram of a tree with a christmas tree caphaving a gas injection line;

FIG. 36 shows a more detailed view of the apparatus of FIG. 35;

FIG. 37 shows a combination of the embodiments of FIGS. 3 and 35;

FIG. 38 shows a further embodiment which is similar to FIG. 23; and

FIG. 39 shows a further embodiment which is similar to FIG. 18.

DETAILED DESCRIPTON OF THE INVENTION

Referring now to the drawings, a typical production manifold on anoffshore oil or gas wellhead comprises a christmas tree with aproduction bore 1 leading from production tubing (not shown) andcarrying production fluids from a perforated region of the productioncasing in a reservoir (not shown). An annulus bore 2 leads to theannulus between the casing and the production tubing and a christmastree cap 4 which seals off the production and annulus bores 1, 2, andprovides a number of hydraulic control channels 3 by which a remoteplatform or intervention vessel can communicate with and operate thevalves in the christmas tree. The cap 4 is removable from the christmastree in order to expose the production and annulus bores in the eventthat intervention is required and tools need to be inserted into theproduction or annulus bores 1, 2.

The flow of fluids through the production and annulus bores is governedby various valves shown in the typical tree of FIG. 1. The productionbore 1 has a branch 10 which is closed by a production wing valve (PWV)12. A production swab valve (PSV) 15 closes the production bore 1 abovethe branch 10 and PWV 12. Two lower valves UPMV 17 and LPMV 18 (which isoptional) close the production bore 1 below the branch 10 and PWV 12.Between UPMV 17 and PSV 15, a crossover port (XOV) 20 is provided in theproduction bore 1 which connects to a the crossover port (XOV) 21 inannulus bore 2.

The annulus bore is closed by an annulus master valve (AMV) 25 below anannulus outlet 28 controlled by an annulus wing valve (AWV) 29, itselfbelow crossover port 21. The crossover port 21 is closed by crossovervalve 30. An annulus swab valve 32 located above the crossover port 21closes the upper end of the annulus bore 2.

All valves in the tree are typically hydraulically controlled (with theexception of LPMV 18 which may be mechanically controlled) by means ofhydraulic control channels 3 passing through the cap 4 and the body ofthe tool or via hoses as required, in response to signals generated fromthe surface or from an intervention vessel.

When production fluids are to be recovered from the production bore 1,LPMV 18 and UPMV 17 are opened, PSV 15 is closed, and PWV 12 is openedto open the branch 10 which leads to the pipeline (not shown). PSV 15and ASV 32 are only opened if intervention is required.

Referring now to FIG. 2, a wellhead cap 40 has a hollow conduit 42 withmetal, inflatable or resilient seals 43 at its lower end which can sealthe outside of the conduit 42 against the inside walls of the productionbore 1, diverting production fluids flowing in through branch 10 intothe annulus between the conduit 42 and the production bore 1 and throughthe outlet 46.

Outlet 46 leads via tubing 216 to processing apparatus 213 (see FIG.17). Many different types of processing apparatus could be used here.For example, the processing apparatus 213 could comprise a pump orprocess fluid turbine, for boosting the pressure of the fluid.Alternatively, or additionally, the processing apparatus could injectgas, steam, sea water, drill cuttings or waste material into the fluids.The injection of gas could be advantageous, as it would give the fluids“lift”, making them easier to pump. The addition of steam has the effectof adding energy to the fluids.

Injecting sea water into a well could be useful to boost the formationpressure for recovery of hydrocarbons from the well, and to maintain thepressure in the underground formation against collapse. Also, injectingwaste gases or drill cuttings etc into a well obviates the need todispose of these at the surface, which can prove expensive andenvironmentally damaging.

The processing apparatus 213 could also enable chemicals to be added tothe fluids, e.g. viscosity moderators, which thin out the fluids, makingthem easier to pump, or pipe skin friction moderators, which minimisethe friction between the fluids and the pipes. Further examples ofchemicals which could be injected are surfactants, refrigerants, andwell fracturing chemicals. Processing apparatus 213 could also compriseinjection water electrolysis equipment. The chemicals/injected materialscould be added via one or more additional input conduits 214.

Additionally, an additional input conduit 214 could be used to provideextra fluids to be injected. An additional input conduit 214 could, forexample, originate from an inlet header (shown in FIG. 30). Likewise, anadditional outlet 212 could lead to an outlet header (also shown in FIG.30) for recovery of fluids.

The processing apparatus 213 could also comprise a fluid riser, whichcould provide an alternative route between the well bore and thesurface. This could be very useful if, for example, the branch 10becomes blocked.

Alternatively, processing apparatus 213 could comprise separationequipment e.g. for separating gas, water, sand/debris and/orhydrocarbons. The separated component(s) could be siphoned off via oneor more additional process conduits 212.

The processing apparatus 213 could alternatively or additionally includemeasurement apparatus, e.g. for measuring the temperature/flowrate/constitution/consistency, etc. The temperature could then becompared to temperature readings taken from the bottom of the well tocalculate the temperature change in produced fluids. Furthermore, theprocessing apparatus 213 could include injection water electrolysisequipment.

Alternative embodiments of the invention (described below) can be usedfor both recovery of production fluids and injection of fluids, and thetype of processing apparatus can be selected as appropriate.

The bore of conduit 42 can be closed by a cap service valve (CSV) 45which is normally open but can close off an inlet 44 of the hollow boreof the conduit 42.

After treatment by the processing apparatus 213 the fluids are returnedvia tubing 217 to the production inlet 44 of the cap 40 which leads tothe bore of the conduit 42 and from there the fluids pass into the wellbore. The conduit bore and the inlet 46 can also have an optionalcrossover valve (COV) designated 50, and a tree cap adapter 51 in orderto adapt the flow diverter channels in the tree cap 40 to a particulardesign of tree head. Control channels 3 are mated with a cap controllingadapter 5 in order to allow continuity of electrical or hydrauliccontrol functions from surface or an intervention vessel.

This embodiment therefore provides a fluid diverter for use with awellhead tree comprising a thin walled diverter conduit and a seal stackelement connected to a modified christmas tree cap, sealing inside theproduction bore of the christmas tree typically above the hydraulicmaster valve, diverting flow through the conduit annulus, and the top ofthe christmas tree cap and tree cap valves to typically a pressureboosting device or chemical treatment apparatus, with the return flowrouted via the tree cap to the bore of the diverter conduit and to thewell bore.

Referring to FIG. 3 a, a further embodiment of a cap 40 a has a largediameter conduit 42 a extending through the open PSV 15 and terminatingin the production bore 1 having seal stack 43 a below the branch 10, anda further seal stack 43 b sealing the bore of the conduit 42 a to theinside of the production bore 1 above the branch 10, leaving an annulusbetween the conduit 42 a and bore 1. Seals 43 a and 43 b are disposed onan area of the conduit 42 a with reduced diameter in the region of thebranch 10. Seals 43 a and 43 b are also disposed on either side of thecrossover port 20 communicating via channel 21 c to the crossover port21 of the annulus bore 2.

Injection fluids enter the branch 10 from where they pass into theannulus between the conduit 42 a and the production bore 1. Fluid flowin the axial direction is limited by the seals 43 a, 43 b and the fluidsleave the annulus via the crossover port 20 into the crossover channel21 c. The crossover channel 21 c leads to the annulus bore 2 and fromthere the fluids pass through the outlet 62 to the pump or chemicaltreatment apparatus. The treated or pressurised fluids are returned fromthe pump or treatment apparatus to inlet 61 in the production bore 1.The fluids travel down the bore of the conduit 42 a and from there,directly into the well bore.

Cap service valve (CSV) 60 is normally open, annulus swab valve 32 isnormally held open, annulus master valve 25 and annulus wing valve 29are normally closed, and crossover valve 30 is normally open. Acrossover valve 65 is provided between the conduit bore 42 a and theannular bore 2 in order to bypass the pump or treatment apparatus ifdesired. Normally the crossover valve 65 is maintained closed.

This embodiment maintains a fairly wide bore for more efficient recoveryof fluids at relatively high pressure, thereby reducing pressure dropsacross the apparatus.

This embodiment therefore provides a fluid diverter for use with amanifold such as a wellhead tree comprising a thin walled diverter withtwo seal stack elements, connected to a tree cap, which straddles thecrossover valve outlet and flowline outlet (which are approximately inthe same horizontal plane), diverting flow from the annular spacebetween the straddle and the existing xmas tree bore, through thecrossover loop and crossover outlet, into the annulus bore (or annulusflowpath in concentric trees), to the top of the tree cap to pressureboosting or chemical treatment apparatus etc, with the return flowrouted via the tree cap and the bore of the conduit.

FIG. 3 b shows a simplified version of a similar embodiment, in whichthe conduit 42 a is replaced by a production bore straddle 70 havingseals 73 a and 73 b having the same position and function as seals 43 aand 43 b described with reference to the FIG. 3 a embodiment. In theFIG. 3 b embodiment, production fluids enter via the branch 10, passthrough the open valve PWV 12 into the annulus between the straddle 70and the production bore 1, through the channel 21 c and crossover port20, through the outlet 62 a to be treated or pressurised etc, and thefluids are then returned via the inlet 61 a, through the straddle 70,through the open LPMV18 and UPMV 17 to the production bore 1.

This embodiment therefore provides a fluid diverter for use with amanifold such as a wellhead tree which is not connected to the tree capby a thin walled conduit, but is anchored in the tree bore, and whichallows full bore flow above the “straddle” portion, but routes flowthrough the crossover and will allow a swab valve (PSV) to functionnormally.

The FIG. 4 a embodiment has a different design of cap 40 c with a widebore conduit 42 c extending down the production bore 1 as previouslydescribed. The conduit 42 c substantially fills the production bore 1,and at its distal end seals the production bore at 83 just above thecrossover port 20, and below the branch 10. The PSV 15 is, as before,maintained open by the conduit 42 c, and perforations 84 at the lowerend of the conduit are provided in the vicinity of the branch 10.Crossover valve 65 b is provided between the production bore 1 andannulus bore 2 in order to bypass the chemical treatment or pump asrequired.

The FIG. 4 a embodiment works in a similar way to the previousembodiments. This embodiment therefore provides a fluid diverter for usewith a wellhead tree comprising a thin walled conduit connected to atree cap, with one seal stack element, which is plugged at the bottom,sealing in the production bore above the hydraulic master valve andcrossover outlet (where the crossover outlet is below the horizontalplane of the flowline outlet), diverting flow through the branch to theannular space between the perforated end of the conduit and the existingtree bore, through perforations 84, through the bore of the conduit 42,to the tree cap, to a treatment or booster apparatus, with the returnflow routed through the annulus bore (or annulus flow path in concentrictrees) and crossover outlet, to the production bore 1 and the well bore.

Referring now to FIG. 4 b, a modified embodiment dispenses with theconduit 42 c of the FIG. 4 a embodiment, and simply provides a seal 83 aabove the XOV port 20 and below the branch 10. This embodiment works inthe same way as the previous embodiments.

This embodiment provides a fluid diverter for use with a manifold suchas a wellhead tree which is not connected to the tree cap by a thinwalled conduit, but is anchored in the tree bore and which routes theflow through the crossover and allows full bore flow for the returnflow, and will allow the swab valve to function normally.

FIG. 5 shows a subsea tree 101 having a production bore 123 for therecovery of production fluids from the well. The tree 101 has a cap body103 that has a central bore 103 b, and which is attached to the tree 101so that the bore 103 b of the cap body 103 is aligned with theproduction bore 123 of the tree. Flow of production fluids through theproduction bore 123 is controlled by the tree master valve 112, which isnormally open, and the tree swab valve 114, which is normally closedduring the production phase of the well, so as to divert fluids flowingthrough the production bore 123 and the tree master valve 112, throughthe production wing valve 113 in the production branch, and to aproduction line for recovery as is conventional in the art.

In the embodiment of the invention shown in FIG. 5, the bore 103 b ofthe cap body 103 contains a turbine or turbine motor 108 mounted on ashaft that is journalled on bearings 122. The shaft extends continuouslythrough the lower part of the cap body bore 103 b and into theproduction bore 123 at which point, a turbine pump, centrifugal pump or,as shown here a turbine pump 107 is mounted on the same shaft. Theturbine pump 107 is housed within a conduit 102.

The turbine motor 108 is configured with inter-collating vanes 108 v and103 v on the shaft and side walls of the bore 103 b respectively, sothat passage of fluid past the vanes in the direction of the arrows 126a and 126 b turns the shaft of the turbine motor 108, and thereby turnsthe vanes of the turbine pump 107, to which it is directly connected.

The bore of the conduit 102 housing the turbine pump 107 is open to theproduction bore 123 at its lower end, but there is a seal between theouter face of the conduit 102 and the inner face of the production bore123 at that lower end, between the tree master valve 112 and theproduction wing branch, so that all production fluid passing through theproduction bore 123 is diverted into the bore of the conduit 102. Theseal is typically an elastomeric or a metal to metal seal.

The upper end of the conduit 102 is sealed in a similar fashion to theinner surface of the cap body bore 103 b, at a lower end thereof, butthe conduit 102 has apertures 102 a allowing fluid communication betweenthe interior of the conduit 102, and the annulus 124, 125 formed betweenthe conduit 102 and the bore of the tree.

The turbine motor 108 is driven by fluid propelled by a hydraulic powerpack H which typically flows in the direction of arrows 126 a and 126 bso that fluid forced down the bore 103 b of the cap turns the vanes 108v of the turbine motor 108 relative to the vanes 103 v of the bore,thereby turning the shaft and the turbine pump 107. These actions drawfluid from the production bore 123 up through the inside of the conduit102 and expels the fluid through the apertures 102 a, into the annulus124, 125 of the production bore. Since the conduit 102 is sealed to thebore above the apertures 102 a, and below the production wing branch atthe lower end of the conduit 102, the fluid flowing into the annulus 124is diverted through the annulus 125 and into the production wing throughthe production wing valve 113 and can be recovered by normal means.

Another benefit of the present embodiment is that the direction of flowof the hydraulic power pack H can be reversed from the configurationshown in FIG. 5, and in such case the fluid flow would be in the reversedirection from that shown by the arrows in FIG. 5, which would allow there-injection of fluid from the production wing valve 113, through theannulus 125, 124 aperture 102 a, conduit 102 and into the productionbore 123, all powered by means of the pump 107 and motor 108 operatingin reverse. This can allow water injection or injection of otherchemicals or substances into all kinds of wells.

In the FIG. 5 embodiment, any suitable turbine or moineau motor can beused, and can be powered by any well known method, such as theelectro-hydraulic power pack shown in FIG. 5, but this particular sourceof power is not essential to the invention.

FIG. 6 shows a different embodiment that uses an electric motor 104instead of the turbine motor 108 to rotate the shaft and the turbinepump 107. The electric motor 104 can be powered from an external or alocal power source, to which it is connected by cables (not shown) in aconventional manner. The electric motor 104 can be substituted for ahydraulic motor or air motor as required.

Like the FIG. 5 embodiment, the direction of rotation of the shaft canbe varied by changing the direction of operation of the motor 104, so asto change the direction of flow of the fluid by the arrows in FIG. 6 tothe reverse direction.

Like the FIG. 5 embodiment, the FIG. 6 assembly can be retrofitted toexisting designs of christmas trees, and can be fitted to many differenttree bore diameters. The embodiments described can also be incorporatedinto new designs of christmas tree as integral features rather than asretrofit assemblies. Also, the embodiments can be fitted to other kindsof manifold apart from trees, such as gathering manifolds, on subsea ortopside wells.

FIG. 7 shows a further embodiment which illustrates that the connectionbetween the shafts of the motor and the pump can be direct or indirect.In the FIG. 7 embodiment, which is otherwise similar to the previous twoembodiments described, the electrical motor 104 powers a drive belt 109,which in turn powers the shaft of the pump 107. This connection betweenthe shafts of the pump and motor permits a more compact design of cap103. The drive belt 109 illustrates a direct mechanical type ofconnection, but could be substituted for a chain drive mechanism, or ahydraulic coupling, or any similar indirect connector such as ahydraulic viscous coupling or well known design.

Like the preceding embodiments, the FIG. 7 embodiment can be operated inreverse to draw fluids in the opposite direction of the arrows shown, ifrequired to inject fluids such as water, chemicals for treatment, ordrill cuttings for disposal into the well.

FIG. 8 shows a further modified embodiment using a hollow turbine shaft102 s that draws fluid from the production bore 123 through the insideof conduit 102 and into the inlet of a combined motor and pump unit 105,107. The motor/pump unit has a hollow shaft design, where the pump rotor107 r is arranged concentrically inside the motor rotor 105 r, both ofwhich are arranged inside a motor stator 105 s. The pump rotor 107 r andthe motor rotor 105 r rotate as a single piece on bearings 122 aroundthe static hollow shaft 102 s thereby drawing fluid from the inside ofthe shaft 102 through the upper apertures 102 u, and down through theannulus 124 between the shaft 102 s and the bore 103 b of the cap 103.The lower portion of the shaft 102 s is apertured at 1021, and the outersurface of the conduit 102 is sealed within the bore of the shaft 102 sabove the lower aperture 1021, so that fluid pumped from the annulus 124and entering the apertures 1021, continues flowing through the annulus125 between the conduit 102 and the shaft 102 s into the production bore123, and finally through the production wing valve 113 for export asnormal.

The motor can be any prime mover of hollow shaft construction, butelectric or hydraulic motors can function adequately in this embodiment.The pump design can be of any suitable type, but a moineau motor, or aturbine as shown here, are both suitable.

Like previous embodiments, the direction of flow of fluid through thepump shown in FIG. 8 can be reversed simply by reversing the directionof the motor, so as to drive the fluid in the opposite direction of thearrows shown in FIG. 8.

Referring now to FIG. 9 a, this embodiment employs a motor 106 in theform of a disc rotor that is preferably electrically powered, but couldbe hydraulic or could derive power from any other suitable source,connected to a centrifugal disc-shaped pump 107 that draws fluid fromthe production bore 123 through the inner bore of the conduit 102 anduses centrifugal impellers to expel the fluid radially outwards intocollecting conduits 124, and thence into an annulus 125 formed betweenthe conduit 102 and the production bore 123 in which it is sealed. Aspreviously described in earlier embodiments, the fluid propelled downthe annulus 125 cannot pass the seal at the lower end of the conduit 102below the production wing branch, and exits through the production wingvalve 113.

FIG. 9 b shows the same pump configured to operate in reverse, to drawfluids through the production wing valve 113, into the conduit 125,across the pump 107, through the re-routed conduit 124′ and conduit 102,and into the production bore 123.

One advantage of the FIG. 9 design is that the disc shaped motor andpump illustrated therein can be duplicated to provide a multi-stage pumpwith several pump units connected in series and/or in parallel in orderto increase the pressure at which the fluid is pumped through theproduction wing valve 113.

Referring now to FIGS. 10 and 11, this embodiment illustrates a piston115 that is sealed within the bore 103 b of the cap 103, and connectedvia a rod to a further lower piston assembly 116 within the bore of theconduit 102. The conduit 102 is again sealed within the bore 103 b andthe production bore 123. The lower end of the piston assembly 116 has acheck valve 119.

The piston 115 is moved up from the lower position shown in FIG. 10 a bypumping fluid into the aperture 126 a through the wall of the bore 103 bby means of a hydraulic power pack in the direction shown by the arrowsin FIG. 10 a. The piston annulus is sealed below the aperture 126 a, andso a build-up of pressure below the piston pushes it upward towards theaperture 126 b, from which fluid is drawn by the hydraulic power pack.As the piston 115 travels upward, a hydraulic signal 130 is generatedthat controls the valve 117, to maintain the direction of the fluid flowshown in FIG. 10 a. When the piston 115 reaches its uppermost stroke,another signal 131 is generated that switches the valve 117 and reversesdirection of fluid from the hydraulic power pack, so that it entersthrough upper aperture 126 b, and is exhausted through lower aperture126 a, as shown in FIG. 11 a. Any other similar switching system couldbe used, and fluid lines are not essential to the invention.

As the piston is moving up as shown in FIG. 10 a, production fluids inthe production bore 123 are drawn into the bore 102 b of the conduit102, thereby filling the bore 102 b of the conduit underneath thepiston. When the piston reaches the upper extent of its travel, andbegins to move downwards, the check valve 119 opens when the pressuremoving the piston downwards exceeds the reservoir pressure in theproduction bore 123, so that the production fluids 123 in the bore 102 bof the conduit 102 flow through the check valve 119, and into theannulus 124 between the conduit 102 and the piston shaft. Once thepiston reaches the lower extent of its stroke, and the pressure betweenthe annulus 124 and the production bore 123 equalises, the check valve119 in the lower piston assembly 116 closes, trapping the fluid in theannulus 124 above the lower piston assembly 116. At that point, thevalve 117 switches, causing the piston 115 to rise again and pull thelower piston assembly 116 with it. This lifts the column of fluid in theannulus 124 above the lower piston assembly 116, and once sufficientpressure is generated in the fluid in the annulus 124 above lower pistonassembly 116, the check valves 120 at the upper end of the annulus open,thereby allowing the well fluid in the annulus to flow through the checkvalves 120 into the annulus 125, and thereby exhausting through wingvalve 113 branch conduit. When the piston reaches its highest point, theupper hydraulic signal 131 is triggered, changing the direction of valve117, and causing the pistons 115 and 116 to move down their respectivecylinders. As the piston 116 moves down once more, the check valve 119opens to allow well fluid to fill the displaced volume above the movinglower piston assembly 116, and the cycle repeats.

The fluid driven by the hydraulic power pack can be driven by othermeans. Alternatively, linear oscillating motion can be imparted to thelower piston assembly 116 by other well-known methods i.e. rotatingcrank and connecting rod, scotch yolk mechanisms etc.

By reversing and/or re-arranging the orientations of the check valves119 and 120, the direction of flow in this embodiment can also bereversed, as shown in FIG. 10 d.

The check valves shown are ball valves, but can be substituted for anyother known fluid valve. The FIGS. 10 and 11 embodiment can beretrofitted to existing trees of varying diameters or incorporated intothe design of new trees.

Referring now to FIGS. 12 and 13, a further embodiment has a similarpiston arrangement as the embodiment shown in FIGS. 10 and 11, but thepiston assembly 115, 116 is housed within a cylinder formed entirely bythe bore 103 b of the cap 103. As before, drive fluid is pumped by thehydraulic power pack into the chamber below the upper piston 115,causing it to rise as shown in FIG. 12 a, and the signal line 130 keepsthe valve 117 in the correct position as the piston 115 is rising. Thisdraws well fluid through the conduit 102 and check valve 119 into thechamber formed in the cap bore 103 b. When the piston has reached itsfull stroke, the signal line 131 is triggered to switch the valve 117 tothe position shown in FIG. 13 a, so that drive fluid is pumped in theother direction and the piston 115 is pushed down. This drives piston116 down the bore 103 b expelling well fluid through the check valves120 (valve 119 is closed), into annulus 124, 125 and through theproduction wing valve 113. In this embodiment the check valve 119 islocated in the conduit 102, but could be immediately above it. Byreversing the orientation of the check valves as in previous embodimentsthe flow of the fluid can be reversed.

A further embodiment is shown in FIGS. 14 and 15, which works in asimilar fashion but has a short diverter assembly 102 sealed to theproduction bore and straddling the production wing branch. The lowerpiston 116 strokes in the production bore 123 above the diverterassembly 102. As before, the drive fluid raises the piston 115 in afirst phase shown in FIG. 14, drawing well fluid through the check valve119, through the diverter assembly 102 and into the upper portion of theproduction bore 123. When the valve 117 switches to the configurationshown in FIG. 15, the pistons 115, 116 are driven down, therebyexpelling the well fluids trapped in the bore 123 u, through the checkvalve 120 (valve 119 is closed) and the production wing valve 113.

FIG. 16 shows a further embodiment, which employs a rotating crank 110with an eccentrically attached arm 110 a instead of a fluid drivemechanism to move the piston 116. The crank 110 is pulling the pistonupward when in the position shown in FIG. 16 a, and pushing it downwardwhen in the position shown in 16 b. This draws fluid into the upper partof the production bore 123 u as previously described. The straddle 102and check valve arrangements as described in the previous embodiment.

It should be noted that the pump does not have to be located in aproduction bore; the pump could be located in any bore of the tree withan inlet and an outlet. For example, the pump and diverter assembly maybe connected to a wing branch of a tree/a choke body as shown in otherembodiments of the invention.

The present invention can also usefully be used in multiple wellcombinations, as shown in FIGS. 18 and 19. FIG. 18 shows a generalarrangement, whereby a production well 230 and an injection well 330 areconnected together via processing apparatus 220.

The injection well 330 can be any of the capped production wellembodiments described above. The production well 230 can also be any ofthe abovedescribed production well embodiments, with outlets and inletsreversed.

Produced fluids from production well 230 flow up through the bore ofconduit 42, exit via outlet 244, and pass through tubing 232 toprocessing apparatus 220, which may also have one or more further inputlines 222 and one or more further outlet lines 224.

Processing apparatus 220 can be selected to perform any of the functionsdescribed above with reference to processing apparatus 213 in the FIG.17 embodiment. Additionally, processing apparatus 220 can also separatewater/gas/oil/sand/debris from the fluids produced from production well230 and then inject one or more of these into injection well 330.Separating fluids from one well and re-injecting into another well viasubsea processing apparatus 220 reduces the quantity of tubing, time andenergy necessary compared to performing each function individually asdescribed with respect to the FIG. 17 embodiment. Processing apparatus220 may also include a riser to the surface, for carrying the producedfluids or a separated component of these to the surface.

Tubing 233 connects processing apparatus 220 back to an inlet 246 of awellhead cap 240 of production well 230. The processing apparatus 220could also be used to inject gas into the separated hydrocarbons forlift and also for the injection of any desired chemicals such as scaleor wax inhibitors. The hydrocarbons are then returned via tubing 233 toinlet 246 and flow from there into the annulus between the conduit 42and the bore in which it is disposed. As the annulus is sealed at theupper and lower ends, the fluids flow through the export line 210 forrecovery.

The horizontal line 310 of injection well 330 serves as an injectionline (instead of an export line). Fluids to be injected can enterinjection line 310, from where they pass via the annulus between theconduit 42 and the bore to the tree cap outlet 346 and tubing 235 intoprocessing apparatus 220. The processing apparatus may include a pump,chemical injection device, and/or separating devices, etc. Once theinjection fluids have been thus processed as required, they can now becombined with any separated water/sand/debris/other waste material fromproduction well 230. The injection fluids are then transported viatubing 234 to an inlet 344 of the cap 340 of injection well 330, fromwhere they pass through the conduit 42 and into the wellbore.

It should be noted that it is not necessary to have any extra injectionfluids entering via injection line 310; all of the injection fluidscould originate from production well 230 instead. Furthermore, as in theprevious embodiments, if processing apparatus 220 includes a riser, thisriser could be used to transport the processed produced fluids to thesurface, instead of passing them back down into the christmas tree ofthe production bore again for recovery via export line 210.

FIG. 19 shows a specific example of the more general embodiment of FIG.18 and like numbers are used to designate like parts. The processingapparatus in this embodiment includes a water injection booster pump 260connected via tubing 235 to an injection well, a production booster pump270 connected via tubing 232 to a production well, and a water separatorvessel 250, connected between the two wells via tubing 232, 233 and 234.Pumps 260, 270 are powered by respective high voltage electricity powerumbilicals 265, 275.

In use, produced fluids from production well 230 exit as previouslydescribed via conduit 42 (not shown in FIG. 19), outlet 244 and tubing232; the pressure of the fluids are boosted by booster pump 270. Theproduced fluids then pass into separator vessel 250, which separates thehydrocarbons from the produced water. The hydrocarbons are returned. toproduction well cap 240 via tubing 233; from cap 240, they are thendirected via the annulus surrounding the conduit 42 to export line 210.

The separated water is transferred via tubing 234 to the wellbore ofinjection well 330 via inlet 344. The separated water enters injectionwell through inlet 344, from where it passes directly into its conduit42 and from there, into the production bore and the depths of injectionwell 330.

Optionally, it may also be desired to inject additional fluids intoinjection well 330. This can be done by closing a valve in tubing 234 toprevent any fluids from entering the injection well via tubing 234. Now,these additional fluids can enter injection well 330 via injection line310 (which was formerly the export line in previous embodiments). Therest of this procedure will follow that described above with referenceto FIG. 17. Fluids entering injection line 310 pass up the annulusbetween conduit 42 (see FIGS. 2 and 17) and the wellbore, are divertedby the seals 43 (see FIG. 2) at the lower end of conduit 42 to travel upthe annulus, and exit via outlet 346. The fluids then pass along tubing235, are pressure boosted by booster pump 260 and are returned viaconduit 237 to inlet 344 of the christmas tree. From here, the fluidspass through the inside of conduit 42 and directly into the wellbore andthe depths of the well 330.

Typically, fluids are injected into injection well 330 from tubing 234(i.e. fluids separated from the produced fluids of production well 230)and from injection line 310 (i.e. any additional fluids) in sequence.Alternatively, tubings 234 and 237 could combine at inlet 344 and thetwo separate lines of injected fluids could be injected into well 330simultaneously.

In the FIG. 19 embodiment, the processing apparatus could comprisesimply the water separator vessel 250, and not include either of thebooster pumps 260, 270.

Although only two connected wells are shown in FIGS. 18 and 19, itshould be understood that more wells could also be connected to theprocessing apparatus.

Two further embodiments of the invention are shown in FIGS. 20 and 21;these embodiments are adapted for use in a traditional and horizontaltree respectively. These embodiments have a diverter assembly 502located partially inside a christmas tree choke body 500. (The internalparts of the choke have been removed, just leaving choke body 500).Choke body 500 communicates with an interior bore of a perpendicularextension of branch 10.

Diverter assembly 502 comprises a housing 504, a conduit 542, an inlet546 and an outlet 544. Housing 504 is substantially cylindrical and hasan axial passage 508 extending along its entire length and a connectinglateral passage adjacent to its upper end; the lateral passage leads tooutlet 544. The lower end of housing 504 is adapted to attach to theupper end of choke body 500 at clamp 506. Axial passage 508 has areduced diameter portion at its upper end; conduit 542 is located insideaxial passage 508 and extends through axial passage 508 as acontinuation of the reduced diameter portion. The rest of axial passage508 beyond the reduced diameter portion is of a larger diameter thanconduit 542, creating an annulus 520 between the outside surface ofconduit 542 and axial passage 508. Conduit 542 extends beyond housing504 into choke body 500, and past the junction between branch 10 and itsperpendicular extension. At this point, the perpendicular extension ofbranch 10 becomes an outlet 530 of branch 10; this is the same outlet asshown in the FIG. 2 embodiment. Conduit 542 is sealed to theperpendicular extension at seal 532 just below the junction. Outlet 544and inlet 546 are typically attached to conduits (not shown) which leadsto and from processing apparatus, which could be any of the processingapparatus described above with reference to previous embodiments.

The diverter assembly 502 can be used to recover fluids from or injectfluids into a well. A method of recovering fluids will now be described.

In use, produced fluids come up the production bore 1, enter branch 10and from there enter annulus 520 between conduit 542 and axial passage508. The fluids are prevented from going downwards towards outlet 530 byseal 532, so they are forced upwards in annulus 520, exiting annulus 520via outlet 544. Outlet 544 typically leads to a processing apparatus(which could be any of the ones described earlier, e.g. a pumping orinjection apparatus). Once the fluids have been processed, they arereturned through a further conduit (not shown) to inlet 546. From here,the fluids pass through the inside of conduit 542 and exit though outlet530, from where they are recovered via an export line.

To inject fluids into the well, the embodiments of FIGS. 20 and 21 canbe used with the flow directions reversed.

It is very common for manifolds of various types to have a choke; theFIG. 20 and FIG. 21 tree embodiments have the advantage that thediverter assembly can be integrated easily with the existing choke bodywith minimal intervention in the well; locating a part of the diverterassembly in the choke body need not even involve removing well cap 40.

A further embodiment is shown in FIG. 22. This is very similar to theFIG. 20 and 21 embodiments, with a choke 540 coupled (e.g. clamped) tothe top of choke body 500. Like parts are designated with like referencenumerals. Choke 540 is a standard subsea choke.

Outlet 544 is coupled via a conduit (not shown) to processing apparatus550, which is in turn connected to an inlet of choke 540. Choke 540 is astandard choke, having an inner passage with an outlet at its lower endand an inlet 541. The lower end of passage 540 is aligned with inlet 546of axial passage 508 of housing 504; thus the inner passage of choke 540and axial passage 508 collectively form one combined axial passage.

A method of recovering fluids will now be described. In use, producedfluids from production bore 1 enter branch 10 and from there enterannulus 520 between conduit 542 and axial passage 508. The fluids areprevented from going downwards towards outlet 530 by seal 532, so theyare forced upwards in annulus 520, exiting annulus 520 via outlet 544.Outlet 544 typically leads to a processing apparatus (which could be anyof the ones described earlier, e.g. a pumping or injection apparatus).Once the fluids have been processed, they are returned through a furtherconduit (not shown) to the inlet 541 of choke 540. Choke 540 may beopened, or partially opened as desired to control the pressure of theproduced fluids. The produced fluids pass through the inner passage ofthe choke, through conduit 542 and exit though outlet 530, from wherethey are recovered via an export line.

The FIG. 22 embodiment is useful for embodiments which also require achoke in addition to the diverter assembly of FIGS. 20 and 21. Again,the FIG. 22 embodiment can be used to inject fluids into a well byreversing the flow paths.

Conduit 542 does not necessarily form an extension of axial passage 508.Alternative embodiments could include a conduit which is a separatecomponent to housing 504; this conduit could be sealed to the upper endof axial passage 508 above outlet 544, in a similar way as conduit 542is sealed at seal 532.

Embodiments of the invention can be retrofitted to many differentexisting designs of manifold, by simply matching the positions andshapes of the hydraulic control channels 3 in the cap, and providingflow diverting channels or connected to the cap which are matched inposition (and preferably size) to the production, annulus and otherbores in the tree or other manifold.

Referring now to FIG. 23, a conventional tree manifold 601 isillustrated having a production bore 602 and an annulus bore 603.

The tree has a production wing 620 and associated production wing valve610. The production wing 620 terminates in a production choke body 630.The production choke body 630 has an interior bore 607 extendingtherethrough in a direction perpendicular to the production wing 620.The bore 607 of the production choke body is in communication with theproduction wing 620 so that the choke body 630 forms an extensionportion of the production wing 620. The opening at the lower end of thebore 607 comprises an outlet 612. In prior art trees, a choke is usuallyinstalled in the production choke body 630, but in the tree 601 of thepresent invention, the choke itself has been removed.

Similarly, the tree 601 also has an annulus wing 621, an annulus wingvalve 611, an annulus choke body 631 and an interior bore 609 of theannulus choke body 631 terminating in an inlet 613 at its lower end.There is no choke inside the annulus choke body 631.

Attached to the production choke body 630 of the production wing 620 isa first diverter assembly 604 in the form of a production insert. Thediverter assembly 604 is very similar to the flow diverter assemblies ofFIGS. 20 to 22.

The production insert 604 comprises a substantially cylindrical housing640, a conduit 642, an inlet 646 and an outlet 644. The housing 640 hasa reduced diameter portion 641 at an upper end and an increased diameterportion 643 at a lower end.

The conduit 642 has an inner bore 649, and forms an extension of thereduced diameter portion 641. The conduit 642 is longer than the housing640 so that it extends beyond the end of the housing 640.

The space between the outer surface of the conduit 642 and the innersurface of the housing 640 forms an axial passage 647, which ends wherethe conduit 642 extends out from the housing 640. A connecting lateralpassage is provided adjacent to the join of the conduit 642 and thehousing 640; the lateral passage is in communication with the axialpassage 647 of the housing 640 and terminates in the outlet 644.

The lower end of the housing 640 is attached to the upper end of theproduction choke body 630 at a clamp 648. The conduit 642 is sealinglyattached inside the inner bore 607 of the choke body 630 at an annularseal 645.

Attached to the annular choke body 631 is a second diverter assembly605. The second diverter assembly 605 is of the same form as the firstdiverter assembly 604. The components of the second diverter assembly605 are the same as those of the first diverter assembly 604, includinga housing 680 comprising a reduced diameter portion 681 and an enlargeddiameter portion 683; a conduit 682 extending from the reduced diameterportion 681 and having a bore 689; an outlet 686; an inlet 684; and anaxial passage 687 formed between the enlarged diameter portion 683 ofthe housing 680 and the conduit 682. A connecting lateral passage isprovided adjacent to the join of the conduit 682 and the housing 680;the lateral passage is in communication with the axial passage 687 ofthe housing 680 and terminates in the inlet 684. The housing 680 isclamped by a clamp 688 on the annulus choke body 631, and the conduit682 is sealed to the inside of the annulus choke body 631 at seal 685.

A conduit 690 connects the outlet 644 of the first diverter assembly 604to a processing apparatus 700. In this embodiment, the processingapparatus 700 comprises bulk water separation equipment, which isadapted to separate water from hydrocarbons. A further conduit 692connects the inlet 646 of the first diverter assembly 604 to theprocessing apparatus 700. Likewise, conduits 694, 696 connect the outlet686 and the inlet 684 respectively of the second diverter assembly 605to the processing apparatus 700. The processing apparatus 700 has pumps820 fitted into the conduits between the separation vessel and the firstand second flow diverter assemblies 604, 605.

The production bore 602 and the annulus bore 603 extend down into thewell from the tree 601, where they are connected to a tubing system 800a, shown in FIG. 24.

The tubing system 800 a is adapted to allow the simultaneous injectionof a first fluid into an injection zone 805 and production of a secondfluid from a production zone 804. The tubing system 800 a comprises aninner tubing 810 which is located inside an outer tubing 812. Theproduction bore 602 is the inner bore of the inner tubing 810. The innertubing 810 has perforations 814 in the region of the production zone804. The outer tubing has perforations 816 in the region of theinjection zone 805. A cylindrical plug 801 is provided in the annulusbore 603 which lies between the outer tubing 812 and the inner tubing810. The plug 801 separates the part of the annulus bore 803 in theregion of the injection zone 805 from the rest of the annulus bore 803.

In use, the produced fluids (typically a mixture of hydrocarbons andwater) enter the inner tubing 810 through the perforations 814 and passinto the production bore 602. The produced fluids then pass through theproduction wing 620, the axial passage 647, the outlet 644, and theconduit 690 into the processing apparatus 700. The processing apparatus700 separates the hydrocarbons from the water (and optionally otherelements such as sand), e.g. using centrifugal separation. Alternativelyor additionally, the processing apparatus can comprise any of the typesof processing apparatus mentioned in this specification.

The separated hydrocarbons flow into the conduit 692, from where theyreturn to the first diverter assembly 604 via the inlet 646. Thehydrocarbons then flow down through the conduit 642 and exit the chokebody 630 at outlet 612, e.g. for removal to the surface.

The water separated from the hydrocarbons by the processing apparatus700 is diverted through the conduit 696, the axial passage 687, and theannulus wing 611 into the annulus bore 603. When the water reaches theinjection zone 805, it passes through the perforations 816 in the outertubing 812 into the injection zone 805.

If desired, extra fluids can be injected into the well in addition tothe separated water. These extra fluids flow into the second diverterassembly 631 via the inlet 613, flow directly through the conduit 682,the conduit 694 and into the processing apparatus 700. These extrafluids are then directed back through the conduit 696 and into theannulus bore 603 as explained above for the path of the separated water.

FIG. 25 shows an alternative form of tubing system 800 b including aninner tubing 820, an outer tubing 822 and an annular seal 821, for usein situations where a production zone 824 is located above an injectionzone 825. The inner tubing 820 has perforations 836 in the region of theproduction zone 824 and the outer tubing 822 has perforations 834 in theregion of the injection zone 825.

The outer tubing 822, which generally extends round the circumference ofthe inner tubing 820, is split into a plurality of axial tubes in theregion of the production zone 824. This allows fluids from theproduction zone 824 to pass between the axial tubes and through theperforations 836 in the inner tubing 820 into the production bore 602.From the production bore 602 the fluids pass upwards into the tree asdescribed above. The returned injection fluids in the annulus bore 603pass through the perforations 834 in the outer tubing 822 into theinjection zone 825.

The FIG. 23 embodiment does not necessarily include any kind ofprocessing apparatus 700. The FIG. 23 embodiment may be used to recoverfluids and/or inject fluids, either at the same time, or differenttimes. The fluids to be injected do not necessarily have to originatefrom any recovered fluids; the injected fluids and recovered fluids mayinstead be two un-related streams of fluids. Therefore, the FIG. 23embodiment does not have to be used for re-injection of recoveredfluids; it can additionally be used in methods of injection.

The pumps 820 are optional.

The tubing system 800 a, 800 b could be any system that allows bothproduction and injection; the system is not limited to the examplesgiven above. Optionally, the tubing system could comprise two conduitswhich are side by side, instead of one inside the other, one of theconduits providing the production bore and the second providing theannulus bore.

FIGS. 26 to 29 illustrate alternative embodiments where the diverterassembly is not inserted within a choke body. These embodimentstherefore allow a choke to be used in addition to the diverter assembly.

FIG. 26 shows a manifold in the form of a tree 900 having a productionbore 902, a production wing branch 920, a production wing valve 910, anoutlet 912 and a production choke 930. The production choke 930 is afull choke, fitted as standard in many christmas trees, in contrast withthe production choke body 630 of the FIG. 23 embodiment, from which theactual choke has been removed. In FIG. 26, the production choke 930 isshown in a fully open position.

A diverter assembly 904 in the form of a production insert is located inthe production wing branch 920 between the production wing valve 910 andthe production choke 930. The diverter assembly 904 is the same as thediverter assembly 604 of the FIG. 23 embodiment, and like parts aredesignated here by like numbers, prefixed by “9”. Like the FIG. 23embodiment, the FIG. 26 housing 940 is attached to the production wingbranch 920 at a clamp 948.

The lower end of the conduit 942 is sealed inside the production wingbranch 920 at a seal 945. The production wing branch 920 includes asecondary branch 921 which connects the part of the production wingbranch 920 adjacent to the diverter assembly 904 with the part of theproduction wing branch 920 adjacent to the production choke 930. A valve922 is located in the production wing branch 920 between the diverterassembly 904 and the production choke 930.

The combination of the valve 922 and the seal 945 prevents productionfluids from flowing directly from the production bore 902 to the outlet912. Instead, the production fluids are diverted into the axial annularpassage 947 between the conduit 942 and the housing 940. The fluids thenexit the outlet 944 into a processing apparatus (examples of which aredescribed above), then re-enter the diverter assembly via the inlet 946,from where they pass through the conduit 942, through the secondarybranch 921, the choke 930 and the outlet 912.

FIG. 27 shows an alternative embodiment of the FIG. 26 design, and likeparts are denoted by like numbers having a prime. In this embodiment,the valve 922 is not needed because the secondary branch 921′ continuesdirectly to the production choke 930′, instead of rejoining theproduction wing branch 920′. Again, the diverter assembly 904′ is sealedin the production wing branch 920′, which prevents fluids from flowingdirectly along the production wing branch 920′, the fluids instead beingdiverted through the diverter assembly 904′.

FIG. 28 shows a further embodiment, in which a diverter assembly 1004 islocated in an extension 1021 of a production wing branch 1020 beneath achoke 1030. The diverter assembly 1004 is the same as the diverterassemblies of FIGS. 26 and 27; it is merely rotated at 90 degrees withrespect to the production wing branch 1020.

The diverter assembly 1004 is sealed within the branch extension 1021 ata seal 1045. A valve 1022 is located in the branch extension 1021 belowthe diverter assembly 1004.

The branch extension 1021 comprises a primary passage 1060 and asecondary passage 1061, which departs from the primary passage 1060 onone side of the valve 1022 and rejoins the primary passage 1060 on theother side of the valve 1022.

Production fluids pass through the choke 1030 and are diverted by thevalve 1022 and the seal 1045 into the axial annular passage 1047 of thediverter assembly 1004 to an outlet 1044. They are then typicallyprocessed by a processing apparatus, as described above, and then theyare returned to the bore 1049 of the diverter assembly 1004, from wherethey pass through the secondary passage 1061, back into the primarypassage 1060 and out of the outlet 1012.

FIG. 29 shows a modified version of the FIG. 28 apparatus, in which likeparts are designated by the same reference number with a prime. In thisembodiment, the secondary passage 1061′ does not rejoin the primarypassage 1060′; instead the secondary passage 1061′ leads directly to theoutlet 1012′. This embodiment works in the same way as the FIG. 6embodiment.

The embodiments of FIGS. 28 and 29 could be modified for use with aconventional christmas tree by incorporating the diverter assembly 1004,1004′ into further pipework attached to the tree, instead of within anextension branch of the tree.

FIG. 30 illustrates an alternative method of using the flow diverterassemblies in the recovery of fluids from multiple wells. The flowdiverter assemblies can be any of the ones shown in the previouslyillustrated embodiments, and are not shown in detail in this Figure; forthis example, the flow diverter assemblies are the production flowdiverter assemblies of FIG. 23.

A first diverter assembly 704 is connected to a branch of a firstproduction well A. The diverter assembly 704 comprises a conduit (notshown) sealed within the bore of a choke body to provide a first flowregion inside the bore of the conduit and a second flow region in theannulus between the conduit and the bore of the choke body. It isemphasised that the diverter assembly 704 is the same as the diverterassembly 604 of FIG. 23; however it is being used in a different way, sosome outlets of FIG. 23 correspond to inlets of FIG. 30 and vice versa.

The bore of the conduit has an inlet 712 and an outlet 746 (inlet 712corresponds to outlet 612 of FIG. 23 and outlet 746 corresponds to inlet646 of FIG. 23). The inlet 712 is in communication with an inlet header701. The inlet header 701 may contain produced fluids from several otherproduction wells (not shown).

The annular passage between the conduit and the choke body is incommunication with the production wing branch of the tree of the firstwell A, and with the outlet 744 (which corresponds to the outlet 644 inFIG. 23).

Likewise, a second diverter assembly 714 is connected to a branch of asecond production well B. The second diverter assembly 714 is the sameas the first diverter assembly 704, and is located in a production wingbranch in the same way. The bore of the conduit of the second diverterassembly has an inlet 756 (corresponding to the inlet 646 in FIG. 23)and an outlet 722 (corresponding to the outlet 612 of FIG. 23). Theoutlet 722 is connected to an output header 703. The output header 703is a conduit for conveying the produced fluids to the surface, forexample, and may also be fed from several other wells (not shown).

The annular passage between the conduit and the inside of the choke bodyconnects the production wing branch to an outlet 754 (which correspondsto the outlet 644 of FIG. 23).

The outlets 746, 744 and 754 are all connected via tubing to the inletof a pump 750. Pump 750 then passes all of these fluids into the inlet756 of the second diverter assembly 714. Optionally, further fluids fromother wells (not shown) are also pumped by pump 750 and passed into theinlet 756.

In use, the second diverter assembly 714 functions in the same way asthe diverter assembly 604 of the FIG. 23 embodiment. Fluids from theproduction bore of the second well B are diverted by the conduit of thesecond diverter assembly 714 into the annular passage between theconduit and the inside of the choke body, from where they exit throughoutlet 754, pass through the pump 750 and are then returned to the boreof the conduit through the inlet 756. The returned fluids pass straightthrough the bore of the conduit and into the outlet header 703, fromwhere they are recovered.

The first diverter assembly 704 functions differently because theproduced fluids from the first well 702 are not returned to the firstdiverter assembly 704 once they leave the outlet 744 of the annulus.Instead, both of the flow regions inside and outside of the conduit havefluid flowing in the same direction. Inside the conduit (the first flowregion), fluids flow upwards from the inlet header 701 straight throughthe conduit to the outlet 746. Outside of the conduit (the second flowregion), fluids flow upwards from the production bore of the first well702 to the outlet 744.

Both streams of upwardly flowing fluids combine with fluids from theoutlet 754 of the second diverter assembly 714, from where they enterthe pump 750, pass through the second diverter assembly into the outletheader 703, as described above.

It should be noted that the tree 601 is a conventional tree but theinvention can also be used with horizontal trees.

One or both of the flow diverter assemblies of the FIG. 23 embodimentcould be located within the production bore and/or the annulus bore,instead of within the production and annular choke bodies.

The processing apparatus 700 could be one or more of a wide variety ofequipment. For example, the processing apparatus 700 could comprise anyof the types of equipment described above with reference to FIG. 17.

The above described flow paths could be completely reversed orredirected for other process requirements.

FIG. 31 shows a further embodiment of a diverter assembly 1110 which isattached to a choke body 1112, which is located in the production wingbranch 1114 of a christmas tree 1116. The production wing branch 1114has an outlet 1118, which is located adjacent to the choke body 1112.The diverter assembly 1110 is attached to the choke body 1112 by a clamp1119. A first valve V1 is located in the central bore of the christmastree and a second valve V2 is located in the production wing branch1114.

The choke body 1112 is a standard subsea choke body from which theoriginal choke has been removed. The choke body 1112 has a bore which isin fluid communication with the production wing branch 1114. The upperend of the bore of the choke body 1112 terminates in an aperture in theupper surface of the choke body 1112. The lower end of the bore of thechoke body communicates with the bore of the production wing branch 1114and the outlet 1118.

The diverter assembly 1110 has a cylindrical housing 1120, which has aninterior axial passage 1122. The lower end of the axial passage 1122 isopen; i.e. it terminates in an aperture. The upper end of the axialpassage 1122 is closed, and a lateral passage 1126 extends from theupper end of the axial passage 1122 to an outlet 1124 in the side wallof the cylindrical housing 1120.

The diverter assembly 1110 has a stem 1128 which extends from the upperclosed end of the axial passage 1122, down through the axial passage1122, where it terminates in a plug 1130. The stem 1128 is longer thanthe housing 1120, so the lower end of the stem 1128 extends beyond thelower end of the housing 1120. The plug 1130 is shaped to engage a seatin the choke body 1112, so that it blocks the part of the productionwing branch 1114 leading to the outlet 1118. The plug therefore preventsfluids from the production wing branch 1114 or from the choke body 1112from exiting via the outlet 1118. The plug is optionally provided with aseal, to ensure that no leaking of fluids can take place.

Before fitting the diverter assembly 1110 to the tree 1116, a choke istypically present inside the choke body 1112 and the outlet 1118 istypically connected to an outlet conduit, which conveys the producedfluids away e.g. to the surface. Produced fluids flow through the boreof the christmas tree 1116, through valves V1 and V2, through theproduction wing branch 1114, and out of outlet 1118 via the choke.

The diverter assembly 1110 can be retrofitted to a well by closing oneor both of the valves V1 and V2 of the christmas tree 1116. Thisprevents any fluids leaking into the ocean whilst the diverter assembly1110 is being fitted. The choke (if present) is removed from the chokebody 1112 by a standard removal procedure known in the art. The diverterassembly 1110 is then clamped onto the top of the choke body 1112 by theclamp 1119 so that the stem 1128 extends into the bore of the choke body1112 and the plug 1130 engages a seat in the choke body 1112 to blockoff the outlet 1118. Further pipework (not shown) is then attached tothe outlet 1124 of the diverter assembly 1110. This further pipework cannow be used to divert the fluids to any desired location. For example,the fluids may be then diverted to a processing apparatus, or acomponent of the produced fluids may be diverted into another well boreto be used as injection fluids.

The valves V1 and V2 are now re-opened which allows the produced fluidsto pass into the production wing branch 1114 and into the choke body1112, from where they are diverted from their former route to the outlet1118 by the plug 1130, and are instead diverted through the diverterassembly 1110, out of the outlet 1124 and into the pipework attached tothe outlet 1124.

Although the above has been described with reference to recoveringproduced fluids from a well, the same apparatus could equally be used toinject fluids into a well, simply by reversing the flow of the fluids.Injected fluids could enter the diverter assembly 1110 at the aperture1124, pass through the diverter assembly 1110, the production wingbranch 14 and into the well. Although this example has described aproduction wing branch 1114 which is connected to the production bore ofa well, the diverter assembly 1110 could equally be attached to anannulus choke body connected to an annulus wing branch and an annulusbore of the well, and used to divert fluids flowing into or out from theannulus bore. An example of a diverter assembly attached to an annuluschoke body has already been described with reference to FIG. 23.

FIG. 32 shows an alternative embodiment of a diverter assembly 1110′attached to the christmas tree 1116, and like parts will be designatedby like numbers having a prime. The christmas tree 1116 is the samechristmas tree 1116 as shown in FIG. 31, so these reference numbers arenot primed.

The housing 1120′ in the diverter assembly 1110′ is cylindrical with anaxial passage 1122′. However, in this embodiment, there is no lateralpassage, and the upper end of the axial passage 1122′ terminates in anaperture 1130′ in the upper end of the housing 1120′, so that the upperend of the housing 1120′ is open. Thus, the axial passage 1122′ extendsall of the way through the housing 1120′ between its lower and upperends. The aperture 1130′ can be connected to external pipework (notshown).

FIG. 33 shows a further alternative embodiment of a diverter assembly1110″, and like parts are designated by like numbers having a doubleprime. This Figure is cut off after the valve V2; the rest of thechristmas tree is the same as that of the previous two embodiments.Again, the christmas tree of this embodiment is the same as those of theprevious two embodiments, and so these reference numbers are not primed.

The housing 1120″ of the FIG. 33 embodiment is substantially the same asthe housing 1120′ of the FIG. 32 embodiment. The housing 1120″ iscylindrical and has an axial passage 1122″ extending therethroughbetween its lower and upper ends, both of which are open. The aperture1130″ can be connected to external pipework (not shown).

The housing 1120″ is provided with an extension portion in the form of aconduit 1132″, which extends from near the upper end of the housing1120″, down through the axial passage 1122″ to a point beyond the end ofthe housing 1120″. The conduit 1132″ is therefore internal to thehousing 1120″, and defines an annulus 1134″ between the conduit 1132″and the housing 1120″.

The lower end of the conduit 1132″ is adapted to fit inside a recess inthe choke body 1112, and is provided with a seal 1136, so that it canseal within this recess, and the length of conduit 1132″ is determinedaccordingly.

As shown in FIG. 33, the conduit 1132″ divides the space within thechoke body 1112 and the diverter assembly 1110″ into two distinct andseparate regions. A first region is defined by the bore of the conduit1132″ and the part of the production wing bore 1114 beneath the chokebody 1112 leading to the outlet 1118. The second region is defined bythe annulus between the conduit 1132″ and the housing 1120″/the chokebody 1112. Thus, the conduit 1132″ forms the boundary between these tworegions, and the seal 1136 ensures that there is no fluid communicationbetween these two regions, so that they are completely separate. TheFIG. 33 embodiment is similar to the embodiments of FIGS. 20 and 21,with the difference that the FIG. 33 annulus is closed at its upper end.

In use, the embodiments of FIGS. 32 and 33 may function in substantiallythe same way. The valves V1 and V2 are closed to allow the choke to beremoved from the choke body 1112 and the diverter assembly 1110′, 1110″to be clamped on to the choke body 1112, as described above withreference to FIG. 31. Further pipework leading to desired equipment isthen attached to the aperture 1130′, 1130″. The diverter assembly 1110′,1110″ can then be used to divert fluids in either direction therethroughbetween the apertures 1118 and 1130′, 1130″.

In the FIG. 32 embodiment, there is the option to divert fluids into orfrom the well, if the valves V1, V2 are open, and the option to excludethese fluids by closing at least one of these valves.

The embodiments of FIGS. 32 and 33 can be used to recover fluids from orinject fluids into a well. Any of the embodiments shown attached to aproduction choke body may alternatively be attached to an annulus chokebody of an annulus wing branch leading to an annulus bore of a well.

In the FIG. 33 embodiment, no fluids can pass directly between theproduction bore and the aperture 1118 via the wing branch 1114, due tothe seal 1136. This embodiment may optionally function as a pipeconnector for a flowline not connected to the well. For example, theFIG. 33 embodiment could simply be used to connect two pipes together.Alternatively, fluids flowing through the axial passage 1132″ may bedirected into, or may come from, the well bore via a bypass line. Anexample of such an embodiment is shown in FIG. 34.

FIG. 34 shows the FIG. 33 apparatus attached to the choke body 1112 ofthe tree 1116. The tree 1116 has a cap 1140, which has an axial passage1142 extending therethrough. The axial passage 1142 is aligned with andconnects directly to the production bore of the tree 1116. A firstconduit 1146 connects the axial passage 1142 to a processing apparatus1148. The processing apparatus 1148 may comprise any of the types ofprocessing apparatus described in this specification. A second conduit1150 connects the processing apparatus 1148 to the aperture 1130″ in thehousing 1120″. Valve V2 is shut and valve V1 is open.

To recover fluids from a well, the fluids travel up through theproduction bore of the tree; they cannot pass into through the wingbranch 1114 because of the V2 valve which is closed, and they areinstead diverted into the cap 1140. The fluids pass through the conduit1146, through the processing apparatus 1148 and they are then conveyedto the axial passage 1122′ by the conduit 1150. The fluids travel downthe axial passage 1122′ to the aperture 1118 and are recovered therefromvia a standard outlet line connected to this aperture.

To inject fluids into a well, the direction of flow is reversed, so thatthe fluids to be injected are passed into the aperture 1118 and are thenconveyed through the axial passage 1122′, the conduit 1150, theprocessing apparatus 1148, the conduit 1146, the cap 1140 and from thecap directly into the production bore of the tree and the well bore.

This embodiment therefore enables fluids to travel between the well boreand the aperture 1118 of the wing branch 1114, whilst bypassing the wingbranch 1114 itself. This embodiment may be especially in wells in whichthe wing branch valve V2 has stuck in the closed position. Inmodifications to this embodiment, the first conduit does not lead to anaperture in the tree cap. For example, the first conduit 1146 couldinstead connect to an annulus branch and an annulus bore; a crossoverport could then connect the annulus bore to the production bore, ifdesired. Any opening into the tree manifold could be used. Theprocessing apparatus could comprise any of the types described in thisspecification, or could alternatively be omitted completely.

These embodiments have the advantage of providing a safe way to connectpipework to the well, without having to disconnect any of the existingpipework, and without a significant risk of fluids leaking from the wellinto the ocean.

The uses of the invention are very wide ranging. The further pipeworkattached to the diverter assembly could lead to an outlet header, aninlet header, a further well, or some processing apparatus (not shown).Many of these processes may never have been envisaged when the christmastree was originally installed, and the invention provides the advantageof being able to adapt these existing trees in a low cost way whilereducing the risk of leaks.

FIG. 35 shows an embodiment of the invention especially adapted forinjecting gas into the produced fluids. A wellhead cap 40 e is attachedto the top of a horizontal tree 400. The wellhead cap 40 e has plugs408, 409; an inner axial passage 402; and an inner lateral passage 404,connecting the inner axial passage 402 with an inlet 406. One end of acoil tubing insert 410 is attached to the inner axial passage 402.Annular sealing plug 412 is provided to seal the annulus between the topend of coil tubing insert 410 and inner axial passage 402. Coil tubinginsert 410 of 2 inch (5 cm) diameter extends downwards from annularsealing plug 412 into the production bore 1 of horizontal christmas tree400.

In use, inlet 406 is connected to a gas injection line 414. Gas ispumped from gas injection line 414 into christmas tree cap 40 e, and isdiverted by plug 408 down into coil tubing insert 410; the gas mixeswith the production fluids in the well. The gas reduces the density ofthe produced fluids, giving them “lift”. The mixture of oil well fluidsand gas then travels up production bore 1, in the annulus betweenproduction bore 1 and coil tubing insert 410. This mixture is preventedfrom travelling into cap 40 e by plug 408; instead it is diverted intobranch 10 for recovery therefrom.

This embodiment therefore divides the production bore into two separateregions, so that the production bore can be used both for injectinggases and recovering fluids. This is in contrast to known methods ofinject fluids via an annulus bore of the well, which cannot work if theannulus bore becomes blocked. In the conventional methods, which rely onthe annulus bore, a blocked annulus bore would mean the entire treewould have to be removed and replaced, whereas the present embodimentprovides a quick and inexpensive alternative.

In this embodiment, the diverter assembly is the coil tubing insert 410and the annular sealing plug 412.

FIG. 36 shows a more detailed view of the FIG. 35 apparatus; theapparatus and the function are the same, and like parts are designatedby like numbers.

FIG. 37 shows the gas injection apparatus of FIG. 35 combined with theflow diverter assembly of FIG. 3 and like parts in these two drawingsare designated here with like numbers. In this figure, outlet 44 andinlet 46 are also connected to inner axial passage 402 via respectiveinner lateral passages.

A booster pump (not shown) is connected between the outlet 44 and theinlet 46. The top end of conduit 42 is sealingly connected at annularseal 416 to inner axial passage 402 above inlet 46 and below outlet 44.Annular sealing plug 412 of coil tubing insert 410 lies between outlet44 and gas inlet 406.

In use, as in the FIG. 35 embodiment, gas is injected through inlet 406into christmas tree cap 40 e and is diverted by plug 408 and annularsealing plug 412 into coil tubing insert 410. The gas travels down thecoil tubing insert 410, which extends into the depths of the well. Thegas combines with the well fluids at the bottom of the wellbore, givingthe fluids “lift” and making them easier to pump. The booster pumpbetween the outlet 44 and the inlet 46 draws the “gassed” producedfluids up the annulus between the wall of production bore 1 and coiltubing insert 410. When the fluids reach conduit 42, they are divertedby seals 43 into the annulus between conduit 42 and coil tubing insert410. The fluids are then diverted by annular sealing plug 412 throughoutlet 44, through the booster pump, and are returned through inlet 46.At this point, the fluids pass into the annulus created between theproduction bore/tree cap inner axial passage and conduit 42, in thevolume bounded by seals 416 and 43. As the fluids cannot pass seals 416,43, they are diverted out of the christmas tree through valve 12 andbranch 10 for recovery.

This embodiment is therefore similar to the FIG. 35 embodiment,additionally allowing for the diversion of fluids to a processingapparatus before returning them to the tree for recovery from the outletof the branch 10. In this embodiment, the conduit 42 is a first diverterassembly, and the coil tubing insert 410 is a second diverter assembly.The conduit 42, which forms a secondary diverter assembly in thisembodiment, does not have to be located in the production bore.Alternative embodiments may use any of the other forms of diverterassembly described in this application (e.g. a diverter assembly on achoke body) in conjunction with the coil tubing insert 410 in theproduction bore.

Modifications and improvements may be incorporated without departingfrom the scope of the invention. For example, as stated above, thediverter assembly could be attached to an annulus choke body, instead ofto a production choke body.

It should be noted that the flow diverters of FIGS. 20, 21, 22, 24, 26to 29 and 32 could also be used in the FIG. 34 method; the FIG. 33embodiment shown in FIG. 34 is just one possible example.

Likewise, the methods shown in FIG. 30 were described with reference tothe FIG. 23 embodiment, but these could be accomplished with any of theembodiments providing two separate flowpaths; these include theembodiments of FIGS. 2 to 6, 17, 20 to 22 and 26 to 29. Withmodifications to the method of FIG. 30, so that fluids from the well Aare only required to flow to the outlet header 703, without any additionof fluids from the inlet header 701, the embodiments only providing asingle flowpath (FIGS. 31 and 32) could also be used. Alternatively, iffluids were only needed to be diverted between the inlet header 701 andthe outlet header 703, without the addition of any fluids from well A,the FIG. 33 embodiment could also be used. Similar considerations applyto well B.

The method of FIG. 18, which involves recovering fluids from a firstwell and injecting at least a portion of these fluids into a secondwell, could likewise be achieved with any of the two-flowpathembodiments of FIGS. 3 to 6, 17, 20 to 22 and 26 to 29. Withmodifications to this method (e.g. the removal of the conduit 234), thesingle flowpath embodiments of FIGS. 31 and FIGS. 32 could be used forthe injection well 330. Such an embodiment is shown in FIG. 38, whichshows a first recovery well A and a second injection well B. Wells A andB each have a tree and a diverter assembly according to FIG. 31. Fluidsare recovered from well A via the diverter assembly; the fluids passinto a conduit C and enter a processing apparatus P. The processingapparatus includes a separating apparatus and a fluid riser R. Theprocessing apparatus separates hydrocarbons from the recovered fluidsand sends these into the fluid riser R for recovery to the surface viathis riser. The remaining fluids are diverted into conduit D which leadsto the diverter assembly of the injection well B, and from there, thefluids pass into the well bore. This embodiment allows diversion offluids whilst bypassing the export line which is normally connected tooutlets 1118.

Therefore, with this modification, single flowpath embodiments couldalso be used for the production well. This method can therefore beachieved with a diverter assembly located in the production/annulus boreor in a wing branch, and with most of the embodiments of diverterassembly described in this specification.

Likewise, the method of FIG. 23, in which recovery and injection occurin the same well, could be achieved with the flow diverters of FIGS. 2to 6 (so that at least one of the flow diverters is located in theproduction bore/annulus bore). A first diverter assembly could belocated in the production bore and a second diverter assembly could beattached to the annulus choke, for example. Further alternativeembodiments (not shown) may have a diverter assembly in the annulusbore, similar to the embodiments of FIGS. 2 to 6 in the production bore.

The FIG. 23 method, in which recovery and injection occur in the samewell, could also be achieved with any of the other diverter assembliesdescribed in the application, including the diverter assemblies which donot provide two separate flowpaths. An example of one such modifiedmethod is shown in FIG. 39. This shows the same tree as FIG. 23, usedwith two FIG. 31 diverter assemblies. In this modified method, none ofthe fluids recovered from the first diverter assembly 640 connected tothe production bore 602 are returned to the first diverter assembly 640.Instead, fluids are recovered from the production bore, are divertedthrough the first diverter assembly 640 into a conduit 690, which leadsto a processing apparatus 700. The processing apparatus 700 could be anyof the ones described in this application. In this embodiment, theprocessing apparatus 700 including both a separating apparatus and afluid riser R to the surface. The apparatus 700 separates hydrocarbonsfrom the rest of the produced fluids, and the hydrocarbons are recoveredto the surface via the fluid riser R, whilst the rest of the fluids arereturned to the tree via conduit 696. These fluids are injected into theannulus bore via the second diverter assembly 680.

Therefore, as illustrated by the examples in FIGS. 38 and 39, themethods of recovery and injection are not limited to methods whichinclude the return of some of the recovered fluids to the diverterassembly used in the recovery, or return of the fluids to a secondportion of a first flowpath.

All of the diverter assemblies shown and described can be used for bothrecovery of fluids and injection of fluids by reversing the flowdirection.

Any of the embodiments which are shown connected to a production wingbranch could instead be connected to an annulus wing branch, or anotherbranch of the tree. The embodiments of FIGS. 31 to 34 could be connectedto other parts of the wing branch, and are not necessarily attached to achoke body. For example, these embodiments could be located in serieswith a choke, at a different point in the wing branch, such as shown inthe embodiments of FIGS. 26 to 29.

1. A method of diverting fluid from a production bore of a subseaproduction tree, the method comprising: removing a choke from a chokeport in a choke body disposed on a branch extending from the tree; andinserting a flow diverter into the choke port wherein the diverter isconfigured to divert fluid from the production bore to the flow diverterand to flow the diverted fluid through the flow diverter, the chokeport, and the choke body to an export line.
 2. The method of claim 1,wherein the flow diverter includes an insert insertable into the chokeport into sealing engagement with the choke body.
 3. A flow diverterassembly adapted for diverting flow between a tree production bore and aflowline, comprising: a tubular body comprising: a first port in fluidcommunication with the tree production bore; a second port in fluidcommunication with the flowline; and a third port capable of receiving achoke insert; and a flow insert receivable in the third port and havingan axial bore for flow therethrough, the flow insert enabling flow to bediverted from between the tree production bore and the flowline tobetween the flow insert axial bore and flowline.
 4. The flow diverterassembly of claim 3 wherein the first and third ports are inlets and thesecond port is an outlet.
 5. The flow diverter assembly of claim 3wherein the first and third ports are outlets and the second port is aninlet.
 6. The flow diverter assembly of claim 3 wherein the third portis in fluid communication with a processing apparatus.
 7. The flowdiverter assembly of claim 6 wherein the processing apparatus isselected from the group consisting of at least one of a pump, processfluid turbine, gas injection apparatus, steam injection apparatus,chemical injection apparatus, materials injection apparatus, gasseparation apparatus, water separation apparatus, sand/debris separationapparatus, hydrocarbon separation apparatus, fluid measurementapparatus, temperature measurement apparatus, flow rate measurementapparatus, constitution measurement apparatus, consistency measurementapparatus, chemical treatment apparatus, pressure boosting apparatus,and water electrolysis apparatus.
 8. A diverter assembly adapted fordisposal on a choke body having a bore, the choke body being part of abranch of a tree assembly having a production bore, the choke body boreforming a flowpath between the production bore and a flowline,comprising: a housing comprising an internal passage; the housing beingmountable to the choke body to access flow through the flowpath, theinternal passage being in fluid communication with the choke body boreto form a flow passage with the choke body bore to flow fluids throughthe internal passage and choke body bore to the flowline; and thehousing internal passage forming part of the flow passage incommunication with the production bore.
 9. A diverter assembly adaptedfor disposal on a choke body having a bore, the choke body being part ofa branch of a tree assembly having a production bore, the choke bodybore forming a flowpath between the production bore and a flowline,comprising: a housing comprising an internal passage; the housing beingmountable to the choke body to divert flow through the flowpath suchthat the internal passage is in fluid communication with the choke bodybore to form a flow passage with the flowline; the housing internalpassage forming part of the flow passage in communication with theproduction bore; and an insert disposed between the housing and chokebody.
 10. A diverter assembly adapted for disposal on a choke bodyhaving a bore, the choke body being part of a branch of a tree assemblyhaving a production bore, the choke body bore forming a flowpath betweenthe production bore and a flowline, comprising: a housing comprising aninternal passage; the housing being mountable to the choke body todivert flow through the flowpath such that the internal passage is influid communication with the choke body bore to form a flow passage withthe flowline; the housing internal passage forming part of the flowpassage in communication with the production bore; and an insertdisposed between the housing and choke body wherein the insert forms aportion of the flow passage through the housing and choke body.
 11. Thediverter assembly of claim 10 wherein the internal passage communicatesfluid between a processing apparatus and a flowline in communicationwith the choke body.
 12. The diverter assembly of claim 10 wherein theinsert seals with the choke body.
 13. The diverter assembly of claim 10wherein the insert is stabbed into an upwardly facing aperture in thechoke body.
 14. A flow diverter assembly disposed on a tree and adaptedfor diverting flow between a tree production bore and a flowline,comprising: a tubular body having: a first bore; a second bore in fluidcommunication with the flowline; and a third bore in fluid communicationwith the tree production bore; the first, second, and third boresmeeting at a common intersection; and an insert receivable in the firstbore and having an axial bore for flow therethrough, the insertdiverting flow from between the tree production bore and the flowline tobetween the first bore and the flowline.
 15. The flow diverter assemblyof claim 14 wherein the insert sealingly engages the tubular body. 16.The flow diverter assembly of claim 14 wherein the insert passes throughthe first bore and is received by the second bore.
 17. The flow diverterassembly of claim 14 wherein the insert passes through the intersectionand closes direct flow between the second and third bores through theintersection.
 18. The flow diverter assembly of claim 14 wherein theinsert is a conduit having a flow bore therethrough.
 19. The flowdiverter assembly of claim 18, wherein the conduit includes a seal toblock fluid communication between the production bore and the flowlineother than through the conduit.
 20. The flow diverter assembly of claim18, the tree assembly including a branch with an inlet and an outlet andwherein the insert is a barrier separating the branch inlet from thebranch outlet.
 21. The flow diverter assembly of claim 18 wherein thefirst bore, second bore, and flow bore are coaxial.
 22. The flowdiverter assembly of claim 14, wherein a part of the diverter assemblyis sealed inside the branch to block fluid communication between twoseparate flow paths through the diverter assembly.
 23. The flow diverterassembly of claim 14 with the tree assembly having a branch with aninlet and an outlet, wherein the third bore of the diverter assembly isin fluid communication with the branch outlet.
 24. The system of claim14, with the tree assembly having a branch with an inlet and an outlet,wherein the diverter assembly comprises a barrier to separate the branchinlet from the branch outlet.
 25. The flow diverter assembly of claim 14wherein the insert is a conduit comprising a flow bore therethrough andis mounted on the housing.
 26. The flow diverter assembly of claim 24wherein the conduit extends outward of the housing.
 27. The flowdiverter assembly of claim 14 wherein the second bore comprises anenlarged diameter portion receiving the insert.
 28. A diverter assemblyfor disposal on a tree assembly having a production bore, comprising: achoke body that is part of a branch of the tree assembly, the choke bodycomprising a bore forming part of a first flowpath in communication withthe production bore; a diverter housing comprising an internal passage;the diverter housing being releasably mountable to the choke body suchthat the internal passage is in fluid communication with the choke bodybore; and the diverter housing internal passage forming part of a secondflowpath, alternative to the first flowpath, in communication with theproduction bore.
 29. A diverter assembly for disposal on a tree assemblyhaving a branch in fluid communication with a production bore,comprising: a choke body comprising: a choke body first bore adapted forfluid communication with the branch; a choke body second bore adapted toreceive a choke; and a choke body export bore; the choke body first borein a first configuration forming part of a first flowpath incommunication with the production bore and the choke body export borewhen the choke is disposed on the choke body; and a diverter housingbeing releasably mountable to the choke body in a second configurationwith an internal passage of the diverter housing being in fluidcommunication with the choke body second bore and choke body exportbore, the diverter housing forming a barrier between the choke bodyfirst bore and the choke body export bore.
 30. The diverter assembly ofclaim 29 wherein the diverter housing internal passage forms part of asecond flowpath, alternative to the first flowpath, in communicationwith the production bore.
 31. A tree intervention method for a subseawell, comprising: closing selected valves in the subsea tree;unconnecting the choke from the choke body; retrieving the choke fromthe choke body; lowering a flow insert to the tree; installing the flowinsert into the choke body; sealing between the choke body and flowinsert; and reopening selected valves on the subsea tree.